摩訶止觀 3.205

3.205

Furthermore, for the four kinds of calming and contemplation to enter the perfect, it is not necessary to wait altogether for practice to be completed before entering the perfect, nor is it necessary to wait altogether for opening the gradual to reveal the sudden before entering the perfect; entry is indeterminate. Why is this? The mind-nature, the direct cause, of all sentient beings is likened to milk; hearing the illuminating-cause Dharma is called placing poison [in it]. The direct cause is uninterrupted, like the four subtleties of milk; although the five flavors transform, the four subtleties are ever present. Therefore, the poison follows the four subtleties, killing people in flavor after flavor. The mind-nature of sentient beings is also like this. The direct cause is not destroyed; the poison of the illuminating cause, following the slowness or quickness of the direct [cause], can burst forth everywhere. It may burst forth through principle, burst forth through teaching, burst forth through practice, or burst forth by achieving realization.