大乘起信論廣釋卷第三．四．五 5.74

5.74

論久習淳熟至速成不退　釋曰。此即勝人能入之中止成得定除障不已。久習等者明止成也。要由不習任運住。任運住者止成之義。以心等者明得定也。止力轉增名漸猛利。既順真如入真三昧。深伏等者。顯入位定契真。現惑永伏染滅善生名信增長。由此速能至不退位。

Treatise: "Practicing for a long time until pure and mature... quickly achieve non-retrogression."
Commentary: This is, among the superior persons who are able to enter, the perfection of calming, attaining absorption, removing obstacles, and not stopping. "Practicing for a long time," etc., explains the perfection of calming. It must be through continuous practice that one abides spontaneously; "abiding spontaneously" is the meaning of calming being perfected. "Because the mind..." etc., explains attaining absorption. When the power of calming increases further, it is called "gradually vigorous and sharp." Since it accords with tathatā, one enters the true samādhi. "Deeply subduing..." etc., shows that entering the stage of absorption accords with the real: manifest afflictions are permanently subdued, defilement is extinguished and good arises, which is called "the growth of faith." Through this, one can quickly reach the stage of non-retrogression.