Why however is it said with a doubt “if it were possible,” when the Lord knows beforehand what is to be? One of two things is implied; that if they are elect, it is not possible; and if it is possible, they are not elect. This doubt therefore in our Lord’s discourse expresses the trembling in the mind of the elect. And He calls them elect, because He sees that they will persevere in faith and good works; for those who are chosen to remain firm are to be tempted to fall by the signs of the preachers of Antichrist.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom in Ezech. i, 9