金剛般若經依天親菩薩論贊略釋秦本義記卷上 1.52

1.52

經。聞是章句乃至由一念生淨信者。第二明信體也。乃至一念生淨信者。一念即一剎那心淨意樂也。信以心淨為性故言淨信矣。

[Sūtra:] "Hearing these passages, even in a single thought-moment they give rise to pure faith." The second explains the essence of faith. "Even in a single thought-moment they give rise to pure faith": a single thought-moment is the mind's pure resolution in a single instant (kṣaṇa). Because faith has purity of mind as its intrinsic nature, it is called "pure faith."