大乘起信論別記 1.14

1.14

言「能示大乘自體」者，是生滅門內之「本覺」。本覺即是生滅之因，是故示於生滅門也。真如門中直云「大乘體」，生滅門中乃云「自體」，不無所以。至下釋中，其義自顯也。

As for "can show the self-essence of the Mahāyāna": this is the innate enlightenment within the gate of arising and ceasing. Innate enlightenment is precisely the cause of arising and ceasing; therefore, it is shown in the gate of arising and ceasing. In the gate of tathatā, it simply says "the essence of the Mahāyāna," whereas in the gate of arising and ceasing, it says "self-essence"; this is not without reason. In the explanation below, its meaning will become evident of itself.