Purification, perfection, and maturation 清淨、圓滿、成熟（生起次第三要素）
Purification, perfection and maturation (Tib. དག་རྫོགས་སྨིན་གསུམ་, Wyl. dag rdzogs smin gsum) –
As taught in the inner tantras, it is generally considered essential to have all three of these factors present when engaging in the tantric practice of the development stage. By meditating in accordance with the processes of the birth, death, and the intermediate state (which comprise cyclic existence)—the four types of birth and so on—all clinging and appearances related to the three levels of existence are refined away and purified.
By meditating on the pure realms, deities, and so forth (which accord with nirvana), the qualities of the fruition, such as the three kayas are perfected in the ground, and the unique potential that allows for these qualities to be actualized comes into existence.
In the same manner, penetrating the vital point of both purity and perfection (or, said differently, of the channels, energies, and essences in the vajra body), one is matured for the symbolic wisdom and true luminosity of the completion stage.
- [TD 1238] Bod rgya tshig mdzod chen mo. Krang dbyi sun, editor. From Deity, Mantra, and Wisdom page 202.