摩訶止觀 3.114

3.114

又佛未出時，諸眾生惡行彰顯，邪非僻倒，過失現前；佛為破此惡故，說於三諦。故知種種行屬破惡，即對治悉檀也。

Furthermore, before the Buddha appeared in the world, the evil actions of sentient beings were blatantly apparent, with heterodox, wrong, and perverted views, and their faults openly displayed. In order to destroy this evil, the Buddha taught the three truths. Hence we know that various kinds of action pertain to destroying evil, which is the therapeutic siddhānta.