大乘百法明門論開宗義決 1.135

1.135

謂此驚覺應起心種等者。謂此作意性能驚覺。若此種子驚起諸餘心心所種令起現行。若至現行引令趣境。此雖與心同時而起。然有驚能。如信與心雖同時起說能淨心。此亦爾故。

Regarding 'Referring to this alarming and awakening the seeds of mind that should arise,' and so forth: this means that the intrinsic nature of this manaskāra is to alarm and awaken. If it is its seed, it alarms and arouses the seeds of the various other cittas and caittas, causing them to arise into manifest activity. If it reaches manifest activity, it leads and directs them to tend toward the object. Although this arises simultaneously with the mind, it has the capacity to alarm. Just as faith, although arising simultaneously with the mind, is said to be able to purify the mind, this is also like that.