法華義疏 4.221

4.221

「尋念過去佛」下，大段第三，明初成道時眾生既不堪受一乘故於一佛乘分別說三。

From "I immediately remembered the past buddhas" down is the third major section: explaining that when he first attained the Path, since sentient beings were unable to receive the ekayāna, he distinguished and taught the three within the one Buddha vehicle.