摩訶止觀 5.133

5.133

三、善巧安心者，善以止觀安於法性也。上深達不思議境，淵奧微密。博運慈悲，亘蓋若此。須行填願，行即止觀也。無明癡惑本是法性，以癡迷故，法性變作無明，起諸顛倒，善不善等。如寒來結水，變作堅水。又如眠來變心，有種種夢。

Third, concerning 'skillfully settling the mind': it means skillfully settling upon dharmatā by means of calming and contemplation. Above, one has profoundly penetrated the inconceivable realm, deep, abstruse, subtle, and secret, and broadly mobilized loving-kindness and compassion, encompassing all in this manner. One must practice to fulfill these vows; practice is itself calming and contemplation. The delusion and folly of avidyā are fundamentally dharmatā; because of folly and delusion, dharmatā transforms into avidyā, giving rise to all inversions, wholesome, unwholesome, and so forth. It is like cold arriving and freezing water, turning it into hard ice; it is also like sleep arriving and transforming the mind, so that various dreams occur.