俱舍論頌疏論本 28.56

28.56

無漏由離染者，無漏等至由一緣得，謂由離染，離下染時，必得上地無漏道故。

As for 'the undefiled, through dispassion,' the undefiled samāpatti is acquired through one condition, namely through dispassion, because when separating from lower defilement, one necessarily acquires the undefiled path of the higher stage.