華嚴一乘教義分齊章 1.20

1.20

二、該攝門者，一切三乘等本來悉是彼一乘法。何以故？以三乘望一乘有二門故，謂不異不一也。

Second, as for the approach of total inclusion: all the Three Vehicles and so forth are originally entirely the dharma of that One Vehicle. Why? Because the Three Vehicles have two aspects in relation to the One Vehicle: namely, non-difference and non-identity.