成唯識論述記 2.245

2.245

述曰：若法由有前後得等皆能生者，應一切時頓生三性，得恒有故。量云：汝善心起時餘所未起善、惡等法現有得者，並應亦起；以有能生得故，如現起善法。更互為量，准此應知。

The Commentary states: If phenomena can all be generated because they have prior or posterior prāptis, then the three natures should be generated simultaneously at all times, because prāpti is constant. The formal argument is: When a wholesome mind arises in your system, the remaining wholesome, unwholesome, and other phenomena that have not yet arisen and presently have prāpti should also all arise; because there is prāpti capable of generating them; like the presently arising wholesome phenomenon. Mutual arguments should be understood by analogy with this.