俱舍論疏 28.31

28.31

論「漸離前支至分為四種」，述立餘三所以也。離伺異初立第二，離喜及伺二異前二立第三，離伺、喜、樂異前三立第四。

The Śāstra says: "Gradually relinquishing the preceding factors [...] it is divided into four kinds." This states the reason for establishing the other three: relinquishing vicāra to differ from the first establishes the second; relinquishing both prīti and vicāra to differ from the previous two establishes the third; relinquishing vicāra, prīti, and sukha to differ from the previous three establishes the fourth.