俱舍論頌疏論本 9.45

9.45

宿諸業名行者，謂宿生中起諸業位，此位五蘊總名為業，業名為行，造作義故。此十二支皆有「位」字，故初句「位」言流至生老死。

"Past karmas are called karmic formations": this refers to the stage of generating various karmas in a past birth. The five skandhas of this stage are collectively named karma; karma is called karmic formations (saṃskāra) because of the meaning of performing action. All twelve of these links have the word "stage" (avasthā); therefore, the word "stage" in the first line carries down to birth, and aging and death.