大乘起信論略述 2.174

2.174

論。修行有五門能成此信　述曰。下答修行。於中有三。初舉數標意。次依數列名。後依名別解。此初也。前雖學起四不德信。若無行成則信不堅不堅之信遇緣便退。故修五行以成四信。

[Treatise:] Cultivation has five gates that can accomplish this faith. [Commentary:] Below, answering about cultivation, there are three parts: first, raising the number to indicate the intent; next, listing the names according to the number; afterwards, explaining them individually according to their names. This is the first. Although previously one learned to arouse the fourfold faithful mind in virtues, if it is not accomplished through practice, then faith is not firm; unformed faith regresses upon meeting conditions. Therefore, one cultivates the five practices to accomplish the four faiths.