首楞嚴義疏注經 1.316

1.316

奪破也。設許合眼對暗名見身中，亦應開眼對明而見自面。內屬於暗尚許返見，面屬於明豈無返見？一成則俱成，一破則俱破，故云若不見面內對不成。

This is depriving it to refute it. Supposing closing the eyes to confront darkness is called seeing within the body, opening the eyes to confront light should also see one's own face. If the inside, which belongs to darkness, is still allowed to be seen turned inward, how could the face, which belongs to light, not be seen turned inward? If one is established, both are established; if one is refuted, both are refuted. Therefore it says: if you do not see your face, the inner confrontation is not established.