勸發菩提心集 1.19

1.19

云何四因？謂諸菩薩種姓具足，是名第一。賴佛菩薩善友攝受，是名第二。於諸眾生多起悲心，是名第三。於極長時生死大苦難行苦行，無有怯畏，是名第四。

What are the four causes? First, bodhisattvas are endowed with the gotra; this is called the first. Relying on the embrace and support of buddhas and bodhisattvas as good friends; this is called the second. Generating great compassion toward all sentient beings; this is called the third. In the face of the great suffering of saṃsāra and hard-to-practice austerities for an extremely long time, having no fear or faintheartedness; this is called the fourth.