大方廣圓覺修多羅了義經略疏 2.780

2.780

夫我難自見，約事證知。但驗自他各殊，即證自中有我。設令修道，捨妄證真，但覺有心，總名我相。

The self is difficult to see by oneself; it is verified and known through affairs. Simply by verifying that self and other are distinct, one realizes that within oneself there is a self. Even if one cultivates the Path, relinquishing delusion to realize the true, as long as one perceives that there is a mind, it is all collectively termed the mark of self.