大乘起信論義記 3.288

3.288

前中言外道經說者，如《仁王經》云「我說三界外，別有一眾生界藏者，是外道《大有經》中說，非七佛說」也。

In the first part, regarding the phrase "the teaching of non-Buddhist scriptures": as the Renwang jing says, "If I were to say that outside the three realms there is separately a realm or store of sentient beings, that is taught in the non-Buddhist Mahāsattva Sūtra, not taught by the seven Buddhas."