Killing Vali by Shri Rama is one of the misunderstood episodes of Ramayana. Some people say it is a controversial topic after seeing some portrays and pictures where it is usually shown Shri Ram hiding himself behind tree kills Vali, so people raise questions and doubts why did Shri Ram kill Vali by hiding himself from his vision? However, this is not controversial at all, It is very much straight forward, as there is no such reference in Valmiki Ramayana anywhere that Shri Ram hid himself behind tree(s) or kept him out of vision from eyes of Vali before piercing Vali by his arrow.
Some people apply their own logics or hearsay to answer if Shri Ram killed Vali from hiding [which is not true], then he did so because Vali had earned some boon through penance, according to which anyone who fights Vali in single-combat would lose half of his strength to Vali, thereby making Vali invulnerable to any enemy. Though any reference of any such boon is not found in Valmiki Ramayana or Sri Ramcharitmanas. Still if someone presumes that Vali had such boon to draw half of the strength of the opponent, then one shouldn't forget Sri Ram's strength is infinite, limitless and immeasurable, and any such boon will fail at very first place to measure Sri Ram's strength, it is just impossible. Therefore, Sri Ram had no need to kill Vali from hiding. However, Vali was certainly a mighty Vanara with great strength.
Shri Ram's sublime conduct - Helping Sugriva and Killing Vali:
Shri Ram being the most compassionate lord, melts on even those who have never been in his service. Shri Ram knew about Vali and Sugreeva both from different persons, While Vali was a powerful Vanara as well as the king of Kishkindha, Sugreeva was ostracized and humiliated by Vali, and being scared of Vali, he was saving his life from Vali in caves of Rishyamuka mountains. Vali had even defeated once Ravana in combat and then to avoid further insult from mighty Vali, Ravana extended his hands of frienship to Vali. Therefore, if Shri Ram had approached Vali in spirit of friendship, Vali could have brought Sita for Sri Rama in a day from the clutches of Ravana.
Still, Shri Ram approached Sugreeva, not Vali, in spirit of friendship and in return, both Sri Rama and Sugriva promised to help each other. But, did a personality like Shri Rama, who had eliminated 14000 thousands army of mighty demons of Khara and Dushana, killed Tadaka, Maricha and Subahu without any fear, who had punished even celestials like the son of Indra in the past really need the help of a monkey, Sugriva, the one living all time in fear of Vali for his own life? Obvious answer is No. Shri Ram, indeed, had no requirement of the help of Sugriva or even Vali, in fact Surgeeva acknowledged this fact in Valmiki Ramayana that Shri Rama does not need any help of others to get back his wife. If such a mighty personality Ram who has no match in whole cosmos in valor takes help of somebody, it is only for giving fame and glory to him out of love and his generosity, because supreme personality of godhead doesn't want anything for him as he is already master of supreme fame and glory. Sri Ram did friendship with Sugriva to make his fame spread, because Sri Rama is the lord who believes in giving glory to his lovers, friends, and servants.
Though, a person whose wife has been stolen and wandering in forest would always wish to befriend with a king and mighty person to get his wife back. But, Shri Ram, being the most compassionate and truly great lord, did nothing sort of this, he did friendship with Sugriva to make him fearless, to restore his wife Ruma, kingdom and pride lost to Vali, again to him. It was a pure Madhurya- Leela of Bhagavan Shri Rama that by befriending an affilcted one like Sugriva, he not only made Sugriva fearless against Vali but also bestowed his intimacy and touch to millions of monkeys and bears!
If Sri Ram had befriended Vali to get his own wife Sita with help of Vali, then how justice would have been brought to Sugriva and his wife Ruma? Shri Ram never looked for his own delight first, the prince charming always delights in delighting others, that's why he is called 'Raama' (the one who delight others).
One should notice here the most important thing that Bhagavan Śrī Rāma himself came to do friendship with Sugreeva, what is the secret behind it As Bhagavan did not need any help of monkeys or others at all to get back Sita as said in Shrimad Bhagavatam? (Same thing is acknowledged by Sugreeva Ji himself in Shri Valmiki Ramayana that Shri Rama does not need help of monkeys or others at all for accomplishing any task.) If Bhagavan makes anyone his friend, it is the greatest honor and the highest achievement for that Jiva.
Although Sugriva Ji had no such quality that He could be eligible to become the friend of Shri Rama and become equal in relation, It is all because Sugreeva Ji was always living in the shelter of Shri Hanuman Ji.
भवता सख्य कामौ तौ भ्रातरौ राम लक्ष्मणौ ।
प्रगृह्य च अर्चयस्व एतौ पूजनीयतमौ उभौ ॥
(श्री वाल्मीकि रामायण ४.५.७)
bhavatā sakhya kāmau tau bhrātarau rāma lakṣmaṇau ।
pragṛhya ca arcayasva ētau pūjanīyatamau ubhau ॥
(śrī vālmīki rāmāyaṇa 4.5.7)
After introducing everything about Shri Rama tattvatah, Hanuman Ji said to Sugreeva “These two brothers Shri Rama and Lakshmana, are interested to make friendship with you... thus you receive these two and worship them, for they are the most venerable (pūjanīyatamau - the most worshipable ones) ones (in whole cosmos)...” Hanumam ji thus advised Sugreeva.
Shri Hanuman ji is here Guru and best friend of Sureeva Ji, Gurudeva advises disciple to worship Bhagavan as the most worshipable (and lovable) one. Hanuman Ji did not leave Sugreeva Ji when he was facing his hardest time. Sugreeva Ji is like the disciple living in shelter of his Guru, and this is the reason Bhagavan himself came and befriended Sureeva. Because of Shri Hanuman Ji, Sugreeva got the highest achievement and honor in form of friendship with Bhagavan Shri Rama, and Bhagavan Shri Rama happily gave his embrace to Sugreeva.
When a Jiva lives always in the shelter of Gurudeva, Bhagavan himself comes and accepts the Jivs as his friend forever, and happily gives his embrace to Jiva, such is the greatness of living always in the shelter of Gurudeva. Thus, Bhagavan, Gurudeva and disciple are in the eternal relationships. A true Guru is an active Suhrid (well-wisher friend) for the disciple
Let's see first how Shri Ram killed Vali :
1. People often translate पराङ्मुख वधम् कृत्वा paraa~Nmukha vadham kR^itvaa = one facing away [from you,] killing him.. as if in hiding Sri Ram killed Vali. However, it is not a good translation Para~Nmukha means Vali who was diverted in attention [from Shri Ram here] was fighting with Sugriva. Therefore, no where it is written Sri Rama hid himself to Kill Vali. Vali's main focus was not on Shri Rama, but Sugreeva as he was foolish in his expectation that Shri Ram will not intervene in the combat between the two brothers, hence he made accusation that I was facing away from you, I didn't think you as enemy, O' Rama! However, Vali forgot, a friend always helps his friend in danger, so Ram had to intervene as per his promise made to Sugreeva.
त्वम् नराधिपतेः पुत्रः प्रथितः प्रिय दर्शनः ।
पराङ्मुख वधम् कृत्वा को अत्र प्राप्तः त्वया गुणः ।
यदहम् युद्ध सम्रब्धः त्वत् कृते निधनम् गतः ॥
(श्री वाल्मीकि रामायण ४.१७.१६)
tvam narādhipatēḥ putraḥ prathitaḥ priya darśanaḥ ।
parāṅmukha vadham kṛtvā kō atra prāptaḥ tvayā guṇaḥ ।
yadaham yuddha samrabdhaḥ tvat kṛtē nidhanam gataḥ ॥
(Śrī Vālmīki Rāmāyaṇa 4.17.16)
"You are a renowned prince with pleasing looks.. but, which kind of death I am getting now, that too when I was in the commotion of conflict with another, alas, that ignoble death is owing to you, and what merit is achieved by you in this undertaking of yours to kill someone who is facing away (diverted in attention) from you (, because of concentrating on fight with Sugriva)... [Valmiki Ramayana 4.17.16]
This was the accusation of Vali on Shri Ram. Tara had advised Vali not to confront Sugreeva, as long as Shri Rama stands guard to him, Vali was very much aware Shri Rama protects Sugreeva. still maddened in his intellect by his might, Vali accepted challenge of Sugriva being protected by Shri Rama who had eliminated so many demons and punished celestials. And this costed his life.
It means when Vali was engaged with somebody else, and as he had no personal enmity with Shri Ram, then why did shri Ram kill him? It doesn't mean Shri Ram killed Vali from back [we will see Shri Ram shot the arrow from front on Vali's chest]. It also doesn't mean Vali didn't see him or Vali was not aware about the vow of Shri Ram that he will eliminate Vali, the foe of his friend Sugreeva. Vali was well aware of Shri Ram's friendship with Sugreeva.
2. Another proof is Shri Ram killed Vali by arrow which directly pierced his chest, which means Shri Ram killed him when he was facing Shri Ram !
मुक्तस्तु वज्र निर्घोषः प्रदीप्त अशनि संनिभः ।
राघवेण महा बाणो वालि वक्षसि पातितः ॥
(श्री वाल्मीकि रामायण ४.१६.३५)
muktastu vajra nirghōṣaḥ pradīpta aśani saṃnibhaḥ ।
rāghavēṇa mahā bāṇō vāli vakṣasi pātitaḥ ॥
(Śrī Vālmīki Rāmāyaṇa 4.16.35)
The arrow released by Shri Ram that has the boom of thunderbolt's thunderclap and the flashes of a lightning fell on the chest of Vali. [Valmiki Ramayana 4.16.35]
3. Vali said His attention was not towards Shri Ram as he was fighting with full attention with Sugriva, was a pure lie told by him. Still, before piercing his chest, Shri Ram was in direct war with Vali, may be from a distance, but it was a direct combat. In fact, a bow-wielder shoots arrows from some distance only.
Here is the proof:
क्षिप्तान् वृक्षान् समाविध्य विपुलाः च शिलाः तथा ।
वाली वज्र समैर् बाणैर् वज्रेण इव निपातितः ॥
(श्री वाल्मीकि रामायण ४.१९.१२)
kṣiptān vṛkṣān samāvidhya vipulāḥ ca śilāḥ tathā ।
vālī vajra samair bāṇair vajrēṇa iva nipātitaḥ ॥
(Śrī Vālmīki Rāmāyaṇa 4.19.12)
Shattering trees and massive boulders that Vali hurled at him (Rama) with thunderbolt like arrows Rama felled Vali as if by thunderbolt. [Valmiki Ramayana 4.19.12]
It means Vali saw Shri Ram, he hurled massive boulders, and trees at him, he attacked shri Ram .. and then, Shri Ram felled all those trees and massive boulders and then, he pierced the chest of Vali directly, it is possible in direct face to face combat only.
why Shri Rama killed Vali :
Now coming to why did he kill Vali? for what reasons? It is very simple to understand why Shri Ram killed Vali.
- it was completely under Shri Ram's jurisdiction to eliminate all evil doers in his kingdom. So, he eliminated Vali who raped the wife of Sugriva, who was like a daughter for Vali.
इक्ष्वाकूणाम् इयम् भूमिः स शैल वन कानना ।
मृग पक्षि मनुष्याणाम् निग्रह अनुग्रहेषु अपि ॥
(श्री वाल्मीकि रामायण ४.१८.६)
ikṣvākūṇām iyam bhūmiḥ sa śaila vana kānanā ।
mṛga pakṣi manuṣyāṇām nigraha anugrahēṣu api ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.6)
Shri Ram answered Vali - "This earth with its mountains, woods, and forests, even along with the authority to condone or condemn the animals, birds, and humans on it belongs to Ikshvaku-s. [Valmiki Ramayana 4.18.6]
Hence Shri Ram being the scion of Ikshvaku eliminated Vali with his arrow.
तस्मिन् नृपति शार्दूल भरते धर्म वत्सले ।
पालयति अखिलाम् पृथ्वीम् कः चरेत् धर्म विप्रियम् ॥
(श्री वाल्मीकि रामायण ४.१८.१०)
tasmin nṛpati śārdūla bharatē dharma vatsalē ।
pālayati akhilām pṛthvīm kaḥ carēt dharma vipriyam ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.10)
While that Bharat, the kingly-tiger and a patron of virtue, is ruling the earth in its entirety, who is there to conduct himself in an unacceptable way to morality on it? [Valmiki Ramayana 4.18.10]
ते वयम् मार्ग विभ्रष्टम् स्वधर्मे परमे स्थिताः ।
भरत आज्ञाम् पुरस्कृत्य निगृह्णीमो यथा विधि ॥
(श्री वाल्मीकि रामायण ४.१८.११)
tē vayam mārga vibhraṣṭam svadharmē paramē sthitāḥ ।
bharata ājñām puraskṛtya nigṛhṇīmō yathā vidhi ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.11)
Abiding in our own pre-eminent righteousness, and even abiding by the order of Bharata we punish him who deviated from the path of morality, according to custom. [Valmiki Ramayana 4.18.11]
Therefore, Shri Rama killed Vali to establish the dharma and morality in his kingdom. It was immorality on the part of Vali to keep the wife of his younger brother as his own wife. Vali was putting a bad indecent immoral example in front of people of his kingdom, so Shri Ram eliminated him to establish the Dharma and morality in the society which is the duty of king or the king's representative.
तत् एतत् कारणम् पश्य यत् अर्थम् त्वम् मया हतः ।
भ्रातुर् वर्तसि भार्यायाम् त्यक्त्वा धर्मम् सनातनम् ॥
(श्री वाल्मीकि रामायण ४.१८.१८)
tat ētat kāraṇam paśya yat artham tvam mayā hataḥ ।
bhrātur vartasi bhāryāyām tyaktvā dharmam sanātanam ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.18)
Realise this reason by which I (Sri Ram) have eliminated you (Vali)... you misbehaved with your brother's wife, forsaking the perpetual tradition. [Valmiki Ramayana 4.18.18]
अस्य त्वम् धरमाणस्य सुग्रीवस्य महात्मनः ।
रुमायाम् वर्तसे कामात् स्नुषायाम् पाप कर्मकृत् ॥
(श्री वाल्मीकि रामायण ४.१८.१९)
asya tvam dharamāṇasya sugrīvasya mahātmanaḥ ।
rumāyām vartasē kāmāt snuṣāyām pāpa karmakṛt ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.19)
While the great-souled Sugreeva is still alive, you with your habit of sinful acts have lustily misbehaved with Sugreeva's wife Ruma, who should be counted as your daughter-in-law. [Valmiki Ramayana4.18.19]
Vali raped the lady who was like a daughter for him, the wife of his own brother! He had habit of such sinful ghastly acts, hence there was no sin in eliminating such a rapist demonic entity in any manner. Shashtra says there is no sin in eliminating the one who lustfully indulges with his daughter, or with his sister, or with the wife of his younger brother. So It was a pure righteous action (Dharma) on part of Shri Ram to punish and eliminate such evil doer Vali.
- Shri Ram acted as Sugreeva's elder brother as well as friend and master, so Ruma became the daughter of Shri Ram! Hence, Shri Ram had all rights to punish the one who raped Ruma.
सुग्रीवेण च मे सख्यम् लक्ष्मणेन यथा तथा ।
दार राज्य निमित्तम् च निःश्रेयसकरः स मे ॥
(श्री वाल्मीकि रामायण ४.१८.२६)
sugrīvēṇa ca mē sakhyam lakṣmaṇēna yathā tathā ।
dāra rājya nimittam ca niḥśrēyasakaraḥ sa mē ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.26)
Shri Ram told Vali: My association with Sugreeva is as good as that with Lakshmana, nevertheless it betided with an understanding to regain sugreeva's wife and kingdom, and he will give succour to me. [Valmiki Ramayana 4-18-26]
So Sugreeva was like younger brother of Shri Ram, hence Shri Ram had to free Ruma by eliminating the one who raped her. This was justice to be done, Shri Ram did pure justice to Ruma and Sugreeva as well as on Vali by punishing him for such immoral act.
☼ Shri Ram had promised Sugreeva to bring justice to him at the time of befriending with him. Afflicted Sugreeva from Vali's injustices, surrendered to Shri Ram, If Shri Ram will not help the afflicted one, then who would help in this whole cosmos?
प्रतिज्ञा च मया दत्ता तदा वानर संनिधौ ।
प्रतिज्ञा च कथम् शक्या मत् विधेन अनवेक्षितुम् ॥
(श्री वाल्मीकि रामायण ४.१८.२७)
pratijñā ca mayā dattā tadā vānara saṃnidhau ।
pratijñā ca katham śakyā mat vidhēna anavēkṣitum ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.27)
I (Sri Ram) gave a promise to Sugreeva at the time of befriending him in the presence of vanara-s, and how is it possible for my kind to dishonour a given promise? [Valmiki Ramayana 4.18.26]
When Vali put arguments that He is mere an animal, not suitable to be eaten by Human [and same time Animals don't follow the Vedic-Dharma], then why did Shri Ram kill him, an animal, as animals don't follow the Vedic-Dharma?
Here, Vali cunningly put arguments to free self from the boundary of dharma. Then, only to refute his logic... Shri Ram told if you are arguing that you are mere an animal, then still there is no sin in eliminating a beast by a prince in hunting. It is never like Ram treated Vali as beast, but to satisfy Vali's heart, Shri Ram answered as per the Dharma of a Kshatriya.
यान्ति राजर्षयः च अत्र मृगयाम् धर्म कोविदाः ।
तस्मात् त्वम् निहतो युद्धे मया बाणेन वानर ।
अयुध्यन् प्रतियुध्यन् वा यस्मात् शाखा मृगो हि असि ॥
(श्री वाल्मीकि रामायण ४.१८.४०)
yānti rājarṣayaḥ ca atra mṛgayām dharma kōvidāḥ ।
tasmāt tvam nihatō yuddhē mayā bāṇēna vānara ।
ayudhyan pratiyudhyan vā yasmāt śākhā mṛgō hi asi ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.40)
Shri Rama told Vali: In this world even the kingly sages well-versed in virtue will go on hunting, (and hunting is no face to face game, as such,) oh, vanara, therefore I felled you in combat with my arrow because you are a tree-branch animal, whether you are not combating with me or combating against me . [Valmiki Ramayana 4.18.40]
Therefore, it was just for countering Vali's logic that he should be treated as mere an animal, and human rules like mating only with wife is not applicable to animals, animals are free to mate with anyone. So when he forcibly established physical relation with the wife of his brother Sugreeva or if he is habitual of such lusty acts, still he should not be expected to follow decent moral conduct and virtues of society.
एवम् उक्तः तु रामेण वाली प्रव्यथितो भृशम् ।
न दोषम् राघवे दध्यौ धर्मे अधिगत निश्चयः ॥
(श्री वाल्मीकि रामायण ४.१८.४४)
ēvam uktaḥ tu rāmēṇa vālī pravyathitō bhṛśam ।
na dōṣam rāghavē dadhyau dharmē adhigata niścayaḥ ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.44)
Vali is much distressed at heart of hearts when Rama replied and refuted all arguments categorically in that way, whereby, deriving certitude about rightness he found no incorrectness with Rama.[Valmiki Ramayana 4.18.44]
Therefore, Vali didn't find any incorrectness in Shri Rama's replies against his arguments, He was satisfied, so He adjoined his palms and prayed O' Rama! You have faultless intellect, You are always engaged in welfare of people.
प्रत्युवाच ततो रामम् प्रांजलिर् वानरेश्वरः ।
यत् त्वम् आत्थ नरश्रेष्ठ तत् थथा एव न अत्र संशयः ॥
(श्री वाल्मीकि रामायण ४.१८.४५)
pratyuvāca tatō rāmam prāṃjalir vānarēśvaraḥ ।
yat tvam āttha naraśrēṣṭha tat thathā ēva na atra saṃśayaḥ ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.45)
That lord of vanara-s, Vali, then replied Rama with adjoined palms, "oh, best one among men, what all you have said is that way proper, undoubtedly. [Valmiki Ramayana 4.18.45]
Vali asks forgiveness from Shri Rama for speaking undesirable and improper words, prays that please don't consider him blameworthy for speaking like that as I spoke those in anguish and ignorance only.
प्रतिवक्तुम् प्रकृष्टे हि न अपकृष्टः तु शक्नुयात् ।
यत् अयुक्तम् मया पूर्वम् प्रमादात् वाक्यम् अप्रियम् ॥
तत्र अपि खलु माम् दोषम् कर्तुम् न अर्हसि राघव ।
त्वम् हि दृष्टार्थ तत्त्वज्ञः प्रजानाम् च हिते रतः ।
कार्य कारण सिद्धौ च प्रसन्ना बुद्धिः अव्यया ॥
(श्री वाल्मीकि रामायण ४.१८.४६-४७)
prativaktum prakṛṣṭē hi na apakṛṣṭaḥ tu śaknuyāt ।
yat ayuktam mayā pūrvam pramādāt vākyam apriyam ॥
tatra api khalu mām dōṣam kartum na arhasi rāghava ।
tvam hi dṛṣṭārtha tattvajñaḥ prajānām ca hitē rataḥ ।
kārya kāraṇa siddhau ca prasannā buddhiḥ avyayā ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.46-47)
Indeed an ignoble [like me, Vali] cannot disprove a nobleman, [the noblest man] Raghava, and with regards to the undesirable and improper words I have unwittingly spoken earlier [to you], in that matter too it will be truly unapt of you to consider me blameworthy, as I spoke them in anguish and ignorance. You alone are the knower of recourses and their real nature, namely probity, prosperity, pleasure seeking, and emancipation; dharma, artha, kaama, moksha ; and you take delight in the welfare of subjects, and your faultless intellect is clear in accomplishing ends by judging the causes and effects. [Valmiki Ramayana 4.18.46-47]
Vali accepts He did grievous sins, and repents, and prays Shri Rama to absolve him.
माम् अपि अवगतम् धर्मात् व्यतिक्रान्त पुरस्कृतम् ।
धर्म संहितया वाचा धर्मज्ञ परिपालय ॥
(श्री वाल्मीकि रामायण ४.१८.४८)
mām api avagatam dharmāt vyatikrānta puraskṛtam ।
dharma saṃhitayā vācā dharmajña paripālaya ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.48)
Oh, Shri Rama, the knower of probity, I am the one who digressed from the rightness and a forerunner among such transgressors, such as I am, give absolution even to me with words abounded with rightness." Vali is thus saying to Rama. [Valmiki Ramayana 4.18.45]
Saying these all words, Vali became full of tears with agonised moan.
बाष्प संरुद्ध कण्ठः तु वाली स आर्त रवः शनैः ।
उवाच रामम् संप्रेक्ष्य पंकलग्न इव द्विपः ॥
(श्री वाल्मीकि रामायण ४.१८.४९)
bāṣpa saṃruddha kaṇṭhaḥ tu vālī sa ārta ravaḥ śanaiḥ ।
uvāca rāmam saṃprēkṣya paṃkalagna iva dvipaḥ ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.49)
Vali who like an elephant plumped in slough continued to say slowly, with tears fully impeding his throat and with an agonised moan, on keenly observing Shri Rama. [Valmiki Ramayana 4.18.45]
Ignoring his wife Tara's advice, Vali accepted the challenge for duel, aspiring elimination at the hand's of Shri Rama! Perhaps, Vali knew already who is Shri Rama in reality.
त्वतः अहम् वधम् आकांक्षयन् वार्यमाणो अपि तारया ॥
सुग्रीवेण सह भ्राता द्वन्द्व युद्धम् उपागतम् ।
इति उक्त्वा वानरो रामम् विरराम हरीश्वरः ॥
(श्री वाल्मीकि रामायण ४.१८.५७-५८)
tvataḥ aham vadham ākāṃkṣayan vāryamāṇō api tārayā ॥
sugrīvēṇa saha bhrātā dvandva yuddham upāgatam ।
iti uktvā vānarō rāmam virarāma harīśvaraḥ ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.57-58)
Though Tara dissuaded me I met with my brother Sugreeva in a duel as though aspiring elimination at your hand.." On saying thus to Shri Rama that vanara, Vali the lord of monkeys' paused for a while. [Valmiki Ramayana 4.18.47-48]
शराभितप्तेन विचेतसा मया प्रदूषितः त्वम् यद् अजानता विभो ।
इदम् महेन्द्रोपम भीम विक्रम प्रसादितः त्वम् क्षम मे नरेश्वर ॥
(श्री वाल्मीकि रामायण ४.१८.६६)
śarābhitaptēna vicētasā mayā pradūṣitaḥ tvam yad ajānatā vibhō ।
idam mahēndrōpama bhīma vikrama prasāditaḥ tvam kṣama mē narēśvara ॥
(Śrī Vālmīki Rāmāyaṇa 4.18.66)
Oh, lord, oh, tremendously braving one, oh, Shri Rama, the lord of people, I blamed you when your arrow sweltered and rendered me imbecile, thus I blamed you unthinkingly for which I may please be pardoned, I seek forgiveness and I appease you for the same. [Valmiki Ramayana 4.18.66]
Vali prayed Shri Rama to look after his dear son Angada, and wife Tara,and also prayed for Sugriva too to look him as like his younger brother Bharat. He requested it will be apt of you, Oh Rama, to see that Sugriva will not look down on Tara treating her as the wife of his rival or on account of maltreating Sugriva's wife Ruma. Shri Rama then consoled Vali with pleasing words you need not be remorseful about your wife, son and others you leave behind, because we take care of them... nor you should bother about us thinking that we have arbitrarily eliminated you, nor necessarily bother about yourself for committing sins, as we took this decision according to rightness and considerateness in your respect, and by virtue of the punishment you are completely divested of your blemish, and as contained in the scriptures on rightness you attained your true nature.
Thus, after seeing all these Pramanas, it is very much evident that Shri Ram killed Vali because there were suitable reasons for his elimination and he didn't kill Vali by hiding him from Vali's vision. Vali saw Shri Ram, he attacked Shri Ram with trees and rocks which Ram countered with his arrows, and then in last Shri Ram killed Vali with his arrow.
It is beautifully answered in Dharmaakuutam, the commentary on Shrimad Valmiki Ramayana.
- When it was promised by Shri Rama that 'I will kill Vali, today only ...' then it may be countered by saying, 'then why killing him from distance, why not Shri Ram confronted him like Sugriva?' If Shri Rama comes to fore, fear may grip Vali, then he may take Ruma, Sugreeva's wife, and to insult, Sugreeva further, Vali may flee away to some distant place with her. Or, Vali may seek shelter in Lanka with Ravana. Or, he may even take refuge in Rama like Sugreeva. Or, on seeing Sugreeva with enough support, he may summon all his Vanara army to fight with Sugreeva and his supporters. Then it will prolong for a time. Then the promise of Rama made to Sugreeva to accord his wife and his kingdom by killing Vali, also prolongs. Justice delayed is denied. Otherwise, if Vali surrenders to Rama, as the killing of a refugee is not a merited act, Shri Rama has to pardon Vali. Whether Vali takes refuse or not, killing Vali on that day itself, and establishing Sugreeva in Kishkindha are the promises made by Rama, at the time of befriending Sugreeva. The word given is to be kept up. So Rama did it and there is no unrighteous deed done by Shri Rama.
Therefore, Killing Vali was a pure Dharma by Shri Ram.