注大乘入楞伽經 8.211

8.211

言如來藏常故，隨其染淨熏習轉變。為作依持，能令諸識知苦樂，與因俱，若生若滅。

This says that because the tathāgatagarbha is permanent, it transforms in accordance with defiled and pure perfumings. Acting as a support, it enables the consciousnesses to know suffering and pleasure, is together with causes, and either arises or ceases.