摩訶止觀 2.101

2.101

Furthermore, the methods of the four kinds of samādhi are each different, but the contemplation of principle is identical. However, the methods of the [first] three practices mostly trigger auxiliary gates to the Way, and also stir up obstacles to the Way; since 'following one's own mind' has few methods, it rarely triggers these things. If one understands only the methods, one cannot penetrate the phenomenal characteristics of the auxiliary [factors] that are triggered; if one understands the contemplation of principle, there are no phenomena that are not penetrated. Moreover, if one does not grasp the meaning of contemplation of principle, the phenomenal auxiliary [factors] to the Way will also not be accomplished; if one grasps the meaning of contemplation of principle, the phenomenal samādhi will be accomplished naturally of its own accord. If one practices the Way through phenomenal methods, one can apply one's mind upon entering the bodhimaṇḍa, but cannot do so upon leaving; 'following one's own mind' is uninterrupted. Methods are confined to the three; contemplation of principle penetrates all four (and so forth).