摩訶止觀 4.124

4.124

○第五、善知識者，是大因緣，所謂化導令得見佛。阿難說：「知識，得道半因緣。」佛言：「不應爾，具足全因緣。」知識有三種：一、外護，二、同行，三、教授。

Fifth, the good friend (kalyāṇamitra): this is a great cause and condition, namely, guiding and instructing so that one attains the sight of the Buddha. Ānanda said, "Good friends are half the causes and conditions for attaining the path." The Buddha said, "It should not be so; they are the complete, whole causes and conditions." There are three kinds of good friends: first, the external protector; second, the fellow practitioner; third, the teacher.