Vishnu as Shri Krishna, delivered Gita as the most hidden knowledge where the soul leaves the body & takes rebirth in a new body. On the other hand Buddha said, there is no soul, it's when the karma is exhausted, the living being is liberated from Samsara. Shri Krishna said only through bhakti one can be delivered and go to His abode as final destination. Buddha taught the liberation is through meditation, which is a sign of a tapasvi. Why would the way to liberation have different opinions?
Well in Vedas, animal sacrifices are prescribed. But there came a time, when real purposes behind the sacrifices probably got forgotten and people started doing the rituals wrongly and were merely slaughtering animals for their own sake but the excuse was that since it is allowed in scriptures, so nothing wrong.
But if animal sacrifice reduces to mere animal slaughter then it does good to nobody. So, it was required to be stopped.
And, in order to stop this practice Lord Vishnu incarnated as Buddha. Now, since animal sacrifice is Vedic, he had to preach an anti-Vedic doctrine to delude the Jinas who were misusing the prescription of animal sacrifices found in the scriptures.
This reason is mentioned in Jayadeva Goswami's Dashavatara Stotram:
nindasi yajña-vidher ahaha s'ruti-i-jâtam |
Decrying slaughter according the rules of Vedic sacrifice,
sadaya-hridaya dars'ita-pas'u-ghâtam |
You are compassionate of heart with the poor animals.
kes'ava dhrita-buddha-s'arîra |
O Kes'ava in the form of Buddha! Hail Hari! Lord of the universe.
jaya jagadîs'a hare, jaya jagadîs'a hare, jaya jagadîs'a hare ||
So, basically, for this particular incarnation, he came to preach against Vedic doctrines and to stop mass slaughtering of innocent animals in the name of Vedic sacrifices.
This page attributed to ISKCON founder Srila Prabhupada, explains why Vishnu reincarnated as Buddha, based on the Srimad Bhagavatham.
Vishnu reincarnated as Buddha to transcendentally cheat atheists into living a moral life and serving God as the Buddha, and also to curb wrongful slaughter of animals in the name of the Vedas.
I summarize the arguments of ISKCON below:
- The Buddha invented a religious system that rejected the Vedas and God, while promoting morality and non-violence.
- His religion rejected the Vedas, because the Vedas were misinterpreted and misused, to unnecessarily kill animals in a sinful manner.
- His religion rejected God because he knew that the atheists would not accept God, but he still wanted to save them somehow, because he was compassionate to them.
- His religion had arguments to convince atheists to live a moral life, without the need for God.
- He tricked the atheists into obeying and serving him, who is actually God, without being called God. Srila Prabhupada called this "transcendental cheating".
- True devotees of Krsna would respect the Buddha because he is an incarnation of God but would ignore the Buddha's teachings, because they knew that it was a false teaching since it rejected God and Vedas.
In the Srimad-Bhagvatam, Lord Buddha is accepted as a saktyavesa avatara, a specially empowered incarnation of the Supreme Lord. Srimad-Bhagvatam, which was compiled by Vyasadeva five thousand years ago, foretold the incarnation of Lord Buddha who appeared just 2,600 years ago, saying Buddha will appear in Gaya Pradesh, in the province of Gaya. "In the beginning of Kali-yuga, the Lord will appear as Lord Buddha, the son of Anjana, in the province of Gaya, just for the purpose of deluding those who are envious of the faithful theist." (Srimad-Bhagavatam 1:3:24). Kesava dhrta buddha sarira - Krsna has accepted the body of Buddha. That is the Vaisnava conception of Lord Buddha.
Lord Buddha appeared at a time when the so-called religionists were falsely using the Vedas to justify violent acts like meat-eating and animal sacrifice. It was the desire of the Supreme Personality of Godhead to end violence being committed in the name of the Vedas. Taking compassion on the poor animals, he appeared as Lord Buddha to preach ahimsa, non-violence, leading the fallen people away from such false interpretations.
At the time of Lord Buddha's appearance, many people had become atheistic, and Srimad-Bhagvatam states that Lord Buddha appeared in order to bewilder this atheistic class of men. Due to their ignorance, the people were being implicated in innumerable sinful activities by unnecessary animal killing in the name of religion. In his preaching, Lord Buddha declined to accept the Vedic principles because the animal-killers would have simply pointed to evidences that in the Vedas there is mention of animal-killing for sacrifice. Therefore, Lord Buddha established a system of religion on the platform of non-violence to stop the nonsense they were engaging in due to a lack of knowledge.
Lord Buddha preached atheism so that the atheists would follow him and thus be tricked into devotional service to Lord Buddha (Krsna). By obeying Lord Buddha, they were actually following God. In order to take the bewildered atheists under his control, he collaborated and said, "Yes, there is no God, but you hear me." Being an actual incarnation of God, this was a kind of transcendental cheating. Those who were followers of Vedic religion, however, did not accept Lord Buddha's religion because it was against the Vedas. In other words, this philosophy is actually meant for bewildering the atheists and should not be accepted by devotees.
Lord Buddha was criticized by the Vedic brahmanas for stopping animal sacrifice, which is recommended in the Vedas as a means of creating new life under very special circumstances. But because the brahmanas had become corrupted and were taking this injunction as a very general thing, Lord Buddha refused to accept the Vedic principles and instead criticized them. Consequently, strict followers of the Vedas would not accept him. The devotee understands why Lord Buddha took this position, however, and while a devotee does not accept the philosophy of Buddhism, he accepts Lord Buddha as incarnation of Lord Krsna and offers obeisances to him. This is the Vaisnava position.
Some claims particular incarnations of God appeared for deluding people! but I think the realized souls were all very respectful to Buddha--be it Ramakrishna, Ramana, Vivekananda or any other respected saint. i did not find a single word in any biography of our great saints condemning Buddha! As Rickross points out very rightly, Buddha appeared to stop mass slaughtering of the innocent animals.
Buddha was the last but one Incarnation of Sri Vishnu as per the scriptures.
Let us know hear from Sri Krishnaprem,(https://en.m.wikipedia.org/wiki/Krishna_Prem),the great Gaudiya Vaishnava on this very topic eightyone years ago. He writes in His 'The Search for Truth'(1938):
It is necessary to say a few words about foolish notion that is unfortunately current in some quarters of this country.It is said that the Buddha, though an Avatara of Vishnu, was one who came in order to delude the Asuras by teaching false doctrines and to destroy them by leading them upon a wrong path.**The authority for this view is sometimes said to be a certain verse in the Srimad-Bhagavata (1/3/24), but in that verse it is stated that He was the son of Anjana and born in the Kikata family. Since the historical Buddha is well-known to have been born in the Lumbini Park near Kapilavastu, it should be quite clear that the writer of the above verse in question either did not know what he was talking about or else was referring to some other person altogether. In either case **it is clear that it is high time that this shameful doctrine should be utterly abandoned.
Then Sri Krishnaprem explains how glorious the life and illumination of Buddha was. He then writes
It is surely a crowning example of the base ingratitude of humanity that One who had thus striven, life after life, for the welfare of others and Who had lit such a Light in the world that by Its rays countless millions have set foot upon the path of salvation should have forgotten in the very country of His birth, or, worse still, have been cruelly slandered by saying that He came to deceive those to save whom He had again and again laid down His life.
He explains beautifully in next few paragraphs of His book that there is no essential difference between the teachings of the Vedas and the teachings of Buddha. He then writes
And what of that Goal,--- the Goal towards which the Buddhist direct his steps?It is that same Goal..beyond all names and all descriptions, being the One Reality from which, as the Shruti says, "speech and mind fall back unable to fathom it".
Sri Krishnaprem sees Buddha as the Manifestation or Incarnation of the same Divinity Who takes birth in each age out of His Love and compassion to preserve Dharma.
Sri Krishna's comments in the Gita on the Vedas and some of Their followers are also worth mentioning while thinking of the criticism of the Vedas by Lord Buddha :
2.42-2.43 O son of Prtha, those undiscerning people who utter this flowery talk which promises birth as a result of rites and duties, and is full of various special rites meant for the attainment of enjoyment and affluence , they remain engrossed in the utterances of the Vedas and declare that nothing else exists; their minds are full of desires and they have heaven as the goal.
2.44 One-pointed conviction does not become established in the minds of those who delight in enjoyment and affluence, and whose intellects are carried away by that (speech).
2.45 O Arjuna, the Vedas [Meaning only the portion dealing with rites and duties (karma-kanda).] have the three qualities as their object. You become free from worldliness, free from the pairs of duality, ever-poised in the ality of sattva, without (desire for) acisition and protection, and self-collected.
In the Tantras, Lord Shiva also says that in the age of kali, the Veda-mantras have all lost their power.
So that Buddha was telling agaainst the Vedas is nothing new in the Sanatana Dharma!
Regarding the 'Atma vs Anatma' debate, Sri Krishnaprem writes
Instead..of assuming that atma and anatma are things of which one is true and the other false, we must remember that they are attempted descriptions in words of some charasteristic of what was experienced without words. Instead of asking which is the true description, we should try to understand what characteristic it was of the experienced reality...We shall then find THERE IS NO CONTRADICTION.
Sri Krishnaprem's entire book can be read here : https://archive.org/details/in.ernet.dli.2015.128125
Actually there is no proper authoritative text which confirms that Budha is the incarnation of Vishnu. All re incarnation of Vishnu's have been to remove certain kingdom, group or persons (raxasas). swamis, sages and rushis should not be confused. The things written by rushis are authentic since one attains that title only after achieving direct contact with the deity. Ex: If you make tapas and make brahma appear and grant you a boon then you are a brahmarshi. Swamis are devotees of a deity and have themselves have not achieved any sidhis. Sages are those who have done some sadhanas but not yet rushis. None of the rushis have said anything about Budha being the avatar of Vishnu. It is just made up later to accommodate him into vaishnavism. All vishnu avatars have done some or other form of killing of certain anti social or negative elements through violence or deception (vamana avatar). His avatars have always been about protecting the humanity from certain imminent evil. Budha gave a new way of attaining moxa, divinity without having to focus on any deity or god. Vishnu has always been about re establishing faith in God not destabilizing it. Budhism has no God as such. Budha itself is a level of awareness or awakening. Anyone can become Budha. Budha is the highest point of awakening. Where as Vaishnavism believes Vishnu is the highest being the closest that you can come to him is after death you become a part of him or be a part of vaikunta. Budha and his defined way of life and attainment is completely in contrast with Vaishnavism. Budhism is takes the way of shiva. Kundalini yoga, Tantric yoga, chakras etc., Budhism has more in common with Shaivism than Vaishnavism and that is why Vaishnavas resisted him during his time and but china (part of mahabharata) where vaishnavism had no strong hold, there his teachings were well received. If you see the history Budhas era was the time when brahmin class was exploiting the society and misusing their status in society. This is when Brahmins instead of earning their livelihood through free spreading of knowledge, religion and dharma started becoming rich by asking devotees to donate heavily to temples, to them and for their groups. ex:- Devotees were asked to donate cows or golden cats to remove certain ailments in their house. Caste system was slowly poking its nose and brahmins made themselves as the most the most privilege class. Looking at all this it is only logical that one of Siva's rudras took the avatar of Budha and gave a path to attain enlightenment without having to rely on God of any kind. Basically Budhism=Hinduism-God. All the mandalas, chakras, yoga, tantric yoga, kundalini yoga which are all part of Shaivism since Shiva is known as mahayogi and kundalini mata his none but his other half Shakti. Sankaracharya on the other hand is known as the Vishnu's avatar and he brought back balance to Bharat again by defeating Budhist scholar in debate and re establishing dharama. In short Shiva and Vishnu has and have always balanced things one after the other when the influence of the other becomes overwhelmingly more than the other. Thus they both bring balance to each other. Vishnu's avatar's have always been about satvic lifestyle with a strong belief in hindu deities or gods and enlightenment through dharma. Shiva's avatars have been impartial to any belief in god but enlightenment through karma or act. This is why Shiva/shakti has always given boons to anyone who did the karma (tapas) irrespective of their without judging their intentions, mind, good or evil. That is why taxasas, manavas, devas all pray and can get boon from him and thus his name bholenath. Anyone else other than shiva/shakti have always been partial to devas and those who fit certain behaviour. Vishnu has never known to give any boons to raxasas or any known anti god or raxasas have prayed to him since has taken devaganas under his protection that he means he is not impartial.