大乘起信論略述 1.173

1.173

論。如風依水至非是水滅　述曰。此舉喻也。文中四句。答前二喻如風依水有動相者。顯妄依真起。若水滅等者。顯真滅妄隨。以水不滅等者。顯真存妄續。以此三句答前問也。唯風滅故等者。妄滅真存。答後問也。

Treatise: "Just as wind relies upon water [to have the characteristic of motion: if the water ceases, then the characteristic of the wind is severed, and there is nowhere for it to rely upon; because the water does not cease, the characteristic of the wind continues; only because the wind ceases does the characteristic of motion cease,] not that the water ceases."
Exposition: This presents the metaphor. There are four clauses in the text, answering the previous two [questions]. The metaphor of "just as wind relies upon water to have the characteristic of motion" reveals delusion arising in reliance upon the true. "If the water ceases..." reveals delusion following the cessation of the true. "Because the water does not cease..." reveals delusion continuing while the true endures. By these three clauses, the former question is answered. "Only because the wind ceases..." shows delusion ceasing while the true endures, answering the latter question.