法華論疏 2.477

2.477

既同一法身，即唯應發一佛心，不發餘心，故令未發菩提心者發菩提心也。既唯一無二，即唯進不退，故已發心者令入法也。問：三菩薩何異？答：初是昔三乘中菩薩，後二是今一乘中菩薩。

Since there is a single identical dharmakāya, one should only generate the single Buddha-mind and not generate any other mind; hence it causes those who have not generated the bodhicitta to generate the bodhicitta. Since it is exclusively one without a second, there is only progressing and no retrogressing; hence it causes those who have already generated the mind to enter the Dharma. Question: How do the three [types of] bodhisattvas differ? Answer: The first are the bodhisattvas in the three vehicles of the past; the latter two are the bodhisattvas in the single vehicle of the present.