瑜伽論記 5.199

5.199

已尋已了別者，初時了別異故。如是於外所乃至觀諸色亦爾者，此釋聞思位准同定中所引止觀，若知若見於彼色亦初尋思及後了別，剩明餘宗解脫等因分別，若薩婆多八解脫一向是因。

Regarding "having sought and having discerned": this is because initial discernment is different. Regarding "in this way, toward the external ... contemplating forms is also thus": this explains that the stages of hearing and thinking are patterned after the calming and insight induced within concentration; whether knowing or seeing, toward that form there is also initial seeking and subsequent discernment. This additionally clarifies the distinguishing of causes of liberation, etc., in other schools: according to the Sarvāstivādins, the eight liberations are exclusively causes.