THE FRUITION OF BUDDHIST PRACTICE is the realization of the three kayas--Dharmakaya, Sambhogakaya, and Nirmanakaya. These are the three bodies of Buddha's being or enlightenment. Dharmakaya corresponds with one's mind, Sambhogakaya with one's speech, and Nirmanakaya with one's body. Dharmakaya is the formless body. It is an undifferentiated state of being which we cannot talk about in terms of either confusion or enlightenment.
The Dharmakaya is something that is always present; it is rediscovered rather than created anew. Because it is atemporal and ahistorical, we cannot attribute change or transformation to it. Because it is passive and indeterminate in nature, Dharmakaya cannot manifest as a medium for one to work for the benefit of others, but it does give rise to the deterministic aspects of Sambhogakaya and Nirmanakaya.
Like the Dharmakaya, the Sambhogakaya is always present. It has to do with mental powers, with the ability of one's mind to manifest in relation to the five wisdoms. In tantric practice, all deities are manifestations of Sambhogakaya because they embody the five different types of wisdom. The Sambhogakaya is connected with communication, both on the verbal and nonverbal levels, and it is also associated with the idea of relating, so that speech here means not just the capacity to use words but the ability to communicate on all levels. Both the Sambhogakaya and Dharmakaya aspects are already embodied within each sentient being, and fruition is a matter of coming to that realization.
Nirmanakaya is the physical aspect of an enlightened being, the medium through which communication and relating can be carried out. It can be said to be new or different, because it is only on the physical level that one can become transformed. In Tibetan the purified body, called ku, is the manifestation of the fully transformed body free from the influence of deeply set and inculcated karmic residues.
Our ordinary physical body is called lu. It is the product of karmic traces and dispositions, and it is lacking in spontaneity and creativity. Through the purification of one's body, speech, and mind, the physical body ceases to be a locus for undesirable negative tendencies, excessive desires, and obsessions, and instead becomes the Nirmanakaya, a medium with extraordinary power to work with and benefit others.
This is an excert from the teaching given by the Ven. Traleg Rinpoche in November 1989 at Karma Triyana Dharmachakra, Woodstock, New York.