大乘起信論義記 3.347

3.347

如脩多羅中，或說有退墮惡趣者，非其實退，但為初學菩薩未入正位而懈怠者，恐怖令彼勇猛故。

As for what is said in sūtras, where it is sometimes said that there are those who retrogress and fall into the evil destinies, this is not actual retrogression; it is only for beginning bodhisattvas who have not entered the correct rank and are indolent, to terrify them and make them vigorous.