Yogācārabhūmi-śāstra, Volume 34 (Part 2)

Original text:由四种行了苦谛相。谓无常行。苦行空行。无我行。由四种行了集谛相。谓因行集行。起行缘行。由四种行了灭谛相。谓灭行静行。妙行离行。由四种行了道谛相。谓道行如行。行行出行。如是名为了相作意。

Explanation: In cultivating the Four Noble Truths, one discerns the characteristic of the truth of suffering through four contemplations: the contemplation of impermanence, the contemplation of suffering, the contemplation of emptiness, and the contemplation of non-self; one discerns the characteristic of the truth of origination through four contemplations: the contemplation of cause, the contemplation of origination, the contemplation of arising, and the contemplation of condition; one discerns the characteristic of the truth of cessation through four contemplations: the contemplation of cessation, the contemplation of tranquility, the contemplation of excellence, and the contemplation of renunciation; and one discerns the characteristic of the truth of the path through four contemplations: the contemplation of the path, the contemplation of suchness, the contemplation of practice, and the contemplation of emergence. Taken together, these dharmas are called the mental engagement of discerning characteristics (laksana-pratisaṃvedana-manaskāra).

This passage introduces the general practice content of the Four Noble Truths. The cultivation of each truth comprises four contemplations, which together make sixteen contemplations, known as the sixteen contemplations of the Four Noble Truths.