法華義疏 5.269

5.269

三乘中大乘即是一乘根性。又此中正明三乘機發，一乘機發在後，故今不說也。

Among the three vehicles, the Mahāyāna is precisely the faculty and nature of the ekayāna. Furthermore, here it specifically explains the activation of the capacity of the three vehicles; the activation of the capacity of the ekayāna comes later, so it is not spoken of now.