摩訶止觀 7.168

7.168

若能勤行五悔方便，助開觀門，一心三諦豁爾開明，如臨淨鏡遍了諸色；於一念中圓解成就，不加功力任運分明，正信堅固無能移動。此名「深信隨喜心」，即初品弟子位也。〈分別功德品〉云：「其有眾生聞佛壽長遠，乃至能生一念信解，所得功德不可限量，能起如來無上之慧。若聞是經而不毀呰，起隨喜心，當知已為深信解相。」即初品文也。

If one can diligently practice the expedients of the five repentances to help open the gate of contemplation, the single mind and three truths will suddenly open in brilliance, like facing a clear mirror and comprehensively seeing all forms; within a single thought-moment, the perfect understanding is accomplished, distinct and clear of itself without applying effort, with correct faith firm and immovable. This is called the 'mind of deep faith and rejoicing,' which is the stage of the disciple of the first rank. The 'Chapter on the Discrimination of Merits' says: 'If there are sentient beings who, hearing of the Buddha's lifespan being so long, can even give rise to a single thought-moment of faith and understanding, the merit they obtain will be boundless, able to give rise to the unsurpassable wisdom of the Tathāgata. If one hears this sutra without disparaging it and gives rise to a mind of rejoicing, one should know that this is already the mark of deep faith and understanding.' This is the text for the first rank.