Yogācārabhūmi-śāstra: Volume 34 (Part 21)

Original Text: How does one observe the nature of impermanence resulting from the transformation caused by internal defilements? It means being able to understand the previously arisen states of mind: whether it is a mind with greed or a mind free from greed; whether it is a mind with hatred or a mind free from hatred; whether it is a mind with delusion or a mind free from delusion. Furthermore, one is able to understand the mind defiled by each and every type of secondary defilement, and also able to understand the mind undefiled by each and every type of secondary defilement. Moreover, one is able to understand how that continuum of mind, through the primary and secondary defilements, sequentially enters states of being subject to change or not subject to change in its preceding and subsequent stages. Having seen this, one then gives rise to this thought: Truly, the nature of all conditioned phenomena is impermanent. Why is this so? Because the transformations produced in the mind due to defilements can be directly observed.

Explanation: How does one observe the nature of impermanence resulting from the transformation caused by defilements within the internal sphere? One is able to understand the previously arisen defiled states of mind: whether it is a mind with greed or without greed; a mind with hatred or without hatred; a mind with delusion or without delusion. One is also able to understand the mind defiled by each type of secondary defilement, and likewise able to understand the mind undefiled by each type of secondary defilement. Furthermore, one is able to understand how the defiled continuum of mind, through the primary and secondary defilements, sequentially enters states of being subject to change or not subject to change in its preceding and subsequent stages. After observing these phenomena, the following thought arises in the mind: Truly, the nature of all such conditioned phenomena is impermanent. Why? Because the transformations produced in the mind due to defilements can be presently observed.