注大乘入楞伽經 6.15

6.15

因上依四平等故，為諸佛子說，即是如來有所說。故舉昔教二夜中間實無言說以請問。

Because it was stated above that 'relying on the four equalities, I speak thus for the Buddha sons,' this implies that the Tathāgata did speak something. Therefore, he raises the former teaching that during the two nights there was truly no speech, in order to make his inquiry.