大方廣圓覺修多羅了義經略疏 2.213

2.213

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.