The three bodies of the Buddha consist of Dharma-kaya (Truth body), Sambhoga-kaya (Enjoyment body), and Nirmana-kaya(Manifestation body).
In the Mahayana philosophy, the personality of the Buddha is given an elaborate treatment. According to this philosophy, the Buddhas have three bodies (trikaya), or three aspects of personality: the Dharmakaya, the Sambhoga-kaya, and the Nirmana-kaya.
After a Buddha has attained Enlightenment, He is the living embodiment of wisdom, compassion, happiness and freedom. At the beginning, there was only one Buddha in the Buddhist tradition. He is the historical Sakyamuni the Buddha. However, even during His lifetime, He made the distinction between Himself as the enlightened, historical individual, on one hand, and Himself as the Embodiment of Truth, on the other. The enlightened personality was known as the 'Rupakaya' (Form-body) or 'Nirmana-kaya' (Manifestation-body). This was the physical body of the Buddha who was born among men, attained Enlightenment, preached the Dhamma and attained Maha Parinibbana. The Manifestation-body or physical body of Buddhas are many and differ from one another.
On the other hand, the principle of Enlightenment which is embodied in Him is known as Dharma-kaya or Truth-body. This is the essence of the Buddha and is independent of the person realizing it. 'Dhamma' in this expression means 'Truth', and does not refer to the verbal teachings which were recorded down in scriptures. The teaching of the Buddha also emanates from the 'Essence' or 'Truth'. So the real, essential Buddha is Truth or the principle of Enlightenment. This idea is clearly stated in the original Pali texts of the Theravada. The Buddha told Vasettha that the Tathagata (the Buddha) was Dharma-kaya, the 'Truth-body' or the 'Embodiment of Truth', as well as Dharmabhuta, 'Truth-become', that is, 'One who has become Truth' (Digha Nikaya). On another occasion, the Buddha told Vakkali:'He who sees the Dhamma (Truth) sees the Tathagata, he who sees the Tathagata sees the Dhamma (Samyutta Nikaya). That is to say, the Buddha is equal to Truth, and all Buddhas are one and the same, being no different from one another in the Dharma-kaya, because Truth is one.'
In the Buddha's lifetime, both the Nirmana-kaya and the Dharma-kaya were united in His. However, after His Parinibbana, the distinction became more pronounced, especially in the Mahayana philosophy. His Manifestation-body was dead and enshrined in the form of relics in stupas: His Dhamma-body is eternally present.
Later, the Mahayana philosophy developed the 'Sambhoga-kaya', the Enjoyment-body. The Sambhoga-kaya can be considered as the body or aspect through which the Buddha enjoyed Himself in the Dhamma, in teaching the Truth, in leading others to the realization of the Truth, and in enjoying the company of good, noble people. This is a selfless, pure, spiritual enjoyment, not to be confused with sensual pleasure. This 'Enjoyment-body' is not categorically mentioned in Theravada texts although it can be appreciated without contradiction if understood in this context. In Mahayana, the Enjoyment-body of the Buddha, unlike the impersonal, abstract principle of the Dharma-kaya, is also considered as a person, though not a human, historical person.
Although the terms Sambhoga-kaya and Dharma-kaya found in the later Pali works come from Mahayana and semi-Mahayana works, scholars from other traditions did not show hostility towards them. Ven Buddhaghosa in his Visuddhi Magga referred thus to the bodies of the Buddha.
'The Buddha is possessed of a beautiful Rupakaya adorned with eighty minor and thirty-two major signs of a great man, and possessed of a Dharmakaya purified in every way and glorified by Sila, Samadhiûr, full of splendor and virtue, incomparable and fully enlightened.'
Though Buddhaghosa's conception was realistic, he was not immune from the religious bias of attributing superhuman power to the Buddha. In the Atthasallini, he said that during the three months' absence of the Buddha, when He was engaged in preaching the Abhidamma to His mother in the Tusita heaven, He created some Nimmita-buddhas as exact replicas of Himself. These Nimmita-buddhas could not be distinguished from the Buddha in voice, words and even the rays of light that issued only by the gods of the higher realms of existence and not by ordinary gods or men. From this description, it is clear that the early Theravadins conceived Buddha's Rupakaya or Sambhoga-kaya as that of a human being, and His Dharma-kaya as the collection of His Dhamma, that is, doctrines and disciplinary rules, collectively.