菩薩瓔珞本業經 1.39

1.39

「佛子！九、心住四等法，所謂化眾生教四諦法，三界非樂為苦，無明習因受生無窮，三空道品無為寂滅。四諦無二，一合相故。

"Buddha-son! Ninth is for the mind to abide in the four immeasurables, that is to say, transforming sentient beings by teaching the Dharma of the four truths: the three realms are not pleasant and are suffering; the cause of accumulation born of ignorance brings about rebirth without end; and the three emptinesses, the aids to enlightenment, and the unconditioned are cessation. The four truths are non-dual, because they are of a single composite mark.