妙法蓮華經玄義 9.142

9.142

今就別說者，破三顯一，正破三情而顯一智。何者？昔若初讚佛乘，眾生沒在苦，既不堪聞大，尋念過去佛所行方便力，亦應說三乘。說三乘已，齊教封三情，不更願好者。今破三執顯於佛智，故言諸佛法久後，要當說真實也。

Speaking now in specific terms, 'shattering the three and revealing the one' specifically shatters the three sentiments and reveals the one wisdom. Why is this? Formerly, if [the Buddha] had initially praised the buddha-yāna, sentient beings, submerged in suffering, would not have been able to hear the great; he then recalled the power of expedients practiced by past buddhas, [realizing] that he should also preach the tri-yāna. Having preached the tri-yāna, conforming to the teaching they clung to the three sentiments, no longer desiring what was superior. Now, shattering the three attachments reveals the Buddha's wisdom; hence it is said: 'The Dharma of all buddhas, after a long time, must surely be spoken in its truth.'