大乘起信論別記 1.6

1.6

言「是心即攝一切法」者，顯大法自體唯是一心，不同小乘一切諸法各有自體皆得作法，故說一心為大乘法。所以依此心法，顯大乘義。

As for the statement "This mind encompasses all dharmas": this reveals that the self-essence of the great dharma is solely the One Mind, unlike the Hīnayāna where all dharmas each have their own self-essence and can all serve as dharmas; therefore, it speaks of the One Mind as the Mahāyāna dharma. For this reason, relying on this mind-dharma, the meaning of Mahāyāna is revealed.