法華義疏 3.292

3.292

雖說五教為顯一理，雖教五人亦為成一人，是為言託於五、意在於一。又所求之道既一，求道之人亦一，故言但教菩薩也。

Although they preach five teachings, it is to reveal the one principle; although they teach five persons, it is also to consummate the one person. This is lodging the words in the five while the intent rests on the one. Furthermore, since the path that is sought is already one, the persons who seek the path are also one; therefore it is said that they only teach bodhisattvas.