起信論疏筆削記 19.46

19.46

如經下，二、引經為據。三試等者，若燒之益粹、打之彌堅、磨而不磷，可謂真矣。共事者，若暫會聚，當共與之從事，從事則體其情性也。情則易變，性則不改，故可知之。如或未辨，久則見之，仁者則久而彌芳，不仁者不可以久處約也。而又未辨，當用善巧觀察，視其所以，觀其所由，察其所安，自然可見其邪正矣。

From "As the sūtra..." onward is the second: citing a sūtra as proof. "Three testings," etc.: If burning it makes it purer, hammering it makes it firmer, and grinding it does not wear it down, it may be called genuine. Regarding "working together": if meeting briefly, one should engage in affairs together with them; through engaging in affairs, one discerns their dispositions and character. Dispositions are easily changed, while character does not alter; thus they can be known. If not yet distinguished, with time it will be seen: the benevolent becomes ever more fragrant over time, while the non-benevolent cannot endure long in adversity. If still not distinguished, one should use skillful observation: look at what they do, observe their motives, and examine what gives them rest; naturally, their heterodoxy or orthodoxy can be seen.