大方廣圓覺修多羅了義經略疏 2.213

2.213

約有幻垢名曰眾生，對離幻垢名為菩薩，故二皆空。然前輪迴及此修證皆云無者，前似岸移，此如鏡像。

Based on the presence of illusory defilement, one is called a sentient being; relative to parting from illusory defilement, one is called a bodhisattva; therefore both are empty. However, as for both the previous saṃsāra and this cultivation and realization being called non-existent: the former is like the moving riverbank, and the latter is like an image in a mirror.