瑜伽論記 22.153

22.153

於中，初釋生等諸苦。言由見生身展轉有故，悟入苦性者，念念生滅名為性苦，即是行苦。

Therein, first, he explains birth and the other various sufferings. Regarding the statement, "Because one sees that the physically born body exists in successive succession, one awakens to and enters into the nature of suffering": moment-by-moment arising and cessation is called the nature of suffering; that is, the suffering of conditioning.