俱舍論疏 28.245

28.245

論「無相三摩地至三有為相」，述第二也。《正理論》云「或復相者是因異名，涅槃無因故名無相。或相謂世蘊上、中、下，涅槃異彼故名無相。」

The Śāstra's [words] from "The signless samādhi (animitta-samādhi)" up to "the three conditioned characteristics" explain the second. The Nyāyānusāra says: "Or again, 'sign' (nimitta) is a different name for cause; because nirvāṇa has no cause, it is called signless. Or, 'sign' refers to the superior, middling, and inferior mundane skandhas; because nirvāṇa is different from them, it is called signless."