俱舍論疏 15.102

15.102

論「住惡戒者至病終難愈」，釋惡戒無作法捨，必至善戒所以。善戒有斷善根捨，惡戒無斷不善根捨者，善戒、惡戒性相違故。斷善根者，非是於先定成惡戒故，至斷因時戒便斷也。若加行善發戒，斷善加行捨。若生得善發戒，隨彼斷上、中、下捨戒。斷欲不善根時，要有修慧加行道時，有定共戒。此戒與彼惡戒相違，已捨戒故，不至斷不善根，故無斷不善根捨也。

On the Śāstra's statement, "For one who abides in bad morality... an illness is ultimately hard to cure": this explains the reason why bad morality has no abandonment through monastic procedure and must await wholesome morality. Wholesome morality has abandonment through cutting off the roots of goodness; that bad morality lacks abandonment through cutting off unwholesome roots is because the natures of wholesome morality and bad morality are mutually opposed. One who cuts off the roots of goodness did not previously necessarily possess bad morality, so when the cause of cutting off arrives, morality is immediately severed. If morality was produced through preparatory (prayoga) goodness, it is abandoned upon cutting off preparatory goodness. If morality was produced through innate (upapattilābhika) goodness, morality is abandoned in accordance with cutting off its superior, middling, or inferior [grades]. When cutting off the unwholesome roots of the desire realm, there must be a restraint concurring with concentration during the preparatory path of wisdom derived from cultivation (bhāvanāmayī prajñā). This restraint opposes that bad morality, and because morality has already been abandoned, it does not reach the cutting off of unwholesome roots; therefore, there is no abandonment through cutting off unwholesome roots.