大乘百法明門論開宗義決 1.249

1.249

性擇別故雖四義殊等者。性為真如。本性有故。擇為擇滅。滅障得故。二義別故開之為二。故五蘊論說有四種。性之與擇皆涅槃性。故涅槃經說三種。

Regarding "because nature and analysis are distinct, although four, the meanings differ, etc.": "nature" refers to tathatā, because it is possessed by fundamental nature; "analysis" refers to analytical cessation, because it is attained by extinguishing obscurations. Because the two meanings are distinct, they are expanded into two; hence the Pañcaskandhaka-śāstra says there are four kinds. Both nature and analysis are the nature of nirvāṇa; therefore the Nirvāṇa-sūtra speaks of three kinds.