維摩經玄疏 3.55

3.55

今言四教者，佛從初得道，至大涅槃，顯示一切法門無非言教也。

Now, speaking of the four teachings: from the Buddha's initial attainment of the Way up to his Mahāparinirvāṇa, all that he revealed as dharma-doors was none other than spoken teaching.