釋禪波羅蜜次第法門 5.168

5.168

復次，此四禪種智定一心故，念常清淨，亦名不動定，亦名不動智慧。於此禪中，若欲轉緣學一切事，隨意成就，一切神通變化，霔雨說法，莫不從此定出。如經說：「佛於四禪為根本。」

Furthermore, because this fourth dhyāna's wisdom-seed absorption is one-pointed, mindfulness is constantly pure; it is also called the unshakeable absorption and also called unshakeable wisdom. In this dhyāna, if one wishes to turn one's attention to learn all matters, they are accomplished at will; all supernormal transformations and showering down the rain of Dharma preaching without exception arise from this absorption. As the sūtra says: 'The Buddha took the fourth dhyāna as the root.'