瑜伽論記 5.106

5.106

三衰退，謂異生有學以說未究竟聖，故知有學皆有三退，謂有病老及死退。

The three declines: this refers to ordinary beings and those in training (śaikṣa) in order to speak of noble ones who are not yet fully accomplished. Hence we know that all those in training have the three declines, namely the decline through illness, through old age, and through death.