John Chrysostom

Having told them how Antichrist cometh, as, for instance, that it will be in a place; He saith how Himself also cometh. How then doth He Himself come? "As the lightning cometh out of the east, and shineth even unto the west, so shall also the coming of the Son of Man be. For wheresoever the carcase is, there also will the eagles be gathered together." How then shineth the lightning? …

Homily on the Gospel of Matthew 76 ↗

Theophylact of Ohrid

For the coming of Christ needs no one to point it out, but it will be utterly clear to all, like the lightning. For just as the lightning is sudden and seen by all, so too will the Lord's coming be visible to everyone on earth. It will not be as in the first coming when He went about from place to place, but at the second coming He will appear in a twinkling of an eye.

Commentary on Matthew ↗

Jerome

For as the lightning comes from the east and shines even to the west, so shall also the coming of the Son of man be. Do not go out, do not believe that the Son of man is in the deserts of the nations or in the inner chambers of heretics; but rather that from the east even unto the west, his faith may shine forth in the Catholic Churches. It must also be said that the second coming of the Savior will not be in humility as before, but in glory to be shown. …

Commentary on Matthew ↗

Thomas Aquinas

For as lightning comes out of the east etc. Here he assigns another reason, because they speak falsely who say that Christ will come in secret; rather, he will come manifestly. And he gives two reasons. One from the manifestation of Christ, another from the gathering of the saints. He says, do not believe that he will not come manifestly: for as lightning comes out of the east, and appears even unto the west, so shall also the coming of the Son of man be; Psalm 49:3: God shall come manifestly. …

Commentary on Matthew ↗