妙法蓮華經玄義 9.146

9.146

住一顯一者，此就佛本意，本以實智化物，佛平等說如一味雨，佛自住大乘，如其所得法，定慧力莊嚴，以此度眾生。若以小乘化，我則墮慳貪，是事為不可。故知從得道夜，常說中道，常說大乘；而眾生罪故，故使如來以毒塗乳，著弊垢衣，方便婆和，引令向大。故言雖說種種道，其實為一乘（云云）。

'Abiding in the one and revealing the one' concerns the Buddha's original intent. Originally, he transformed beings through real wisdom: 'The Buddha preaches impartially, like rain of a single flavor'; 'The Buddha himself abides in the Great Vehicle; in accordance with the Dharma he has attained, adorned with the power of samādhi and wisdom, with this he delivers sentient beings. If I were to transform [them] through the small vehicle, I would fall into stinginess and greed; this cannot be.' Thus we know that from the night he attained the Way, he constantly preached the middle way and constantly preached the Great Vehicle; yet because of the sins of sentient beings, the Tathāgata was made to smear milk with poison, wear worn and soiled garments, and harmoniously employ expedients, guiding them toward the Great. Hence it is said: 'Although he preaches various paths, they are in truth for the sake of the eka-yāna' (and so on).