妙法蓮華經文句 6.8

6.8

或曾發心，名出三界，而復退還名之為入。如人舉足欲出門側而反，亦名為出亦名還入也。又理性本淨非三界法，因無明故而起戲論便有生死，故云「先因遊戲來入」也。

Perhaps they once generated the mind [for enlightenment], which is called emerging from the triple world, yet retrogressed again, which is called entering. Just as when a person raises his foot intending to exit by the side of the gate and then turns back, this is both called emerging and called returning within. Furthermore, the essential nature is originally pure and is not an entity of the triple world; on account of ignorance, conceptual proliferations arise and there is birth and death, hence it says "previously entered on account of play".