大乘起信論廣釋卷第三．四．五 3.40

3.40

論。三者執取相至心起著故　釋曰。於苦樂境不了虛妄深起取著名執取相。謂即於前相續所念苦樂境上復深取著領納不捨。故言心起著等。

[Treatise:] Third is the characteristic of grasping [… down to …] because the mind gives rise to attachment.
[Commentary:] Regarding objects of pain and pleasure, not understanding that they are fictitious and profoundly giving rise to grasping and attachment is named 'characteristic of grasping'. That is, regarding the objects of pain and pleasure recollected in the preceding continuity, one further profoundly grasps them, taking them in and not letting go; hence it says: 'the mind gives rise to attachment,' and so forth.