大乘起信論義記 3.123

3.123

問曰：若如是義者，一切眾生悉有真如，等皆熏習，云何有信、無信，無量前後差別？皆應一時自知有真如法，勤修方便等入涅槃。

The question asks: If this is the meaning, all sentient beings possess tathatā and are equally perfumed; how is it that there is faith and lack of faith, and countless differences in prior and posterior? All should simultaneously know of themselves that they possess the dharma of tathatā, diligently cultivate skillful means, and equally enter nirvāṇa.