John Gill Commentary Matthew 24:27

"For as the lightning cometh forth from the east, and is seen even unto the west; so shall be the coming of the Son of man." — Matthew 24:27 (ASV)

For as the lightning comes out of the east The eastern part of the horizon, and shines even to the west; to the western part of it, with great clearness; in a moment; in the twinkling of an eye, filling the whole intermediate space; so shall also the coming of the son of man be;

which must be understood not of his last coming to judgment, though that will be sudden, visible, and universal; he will at once come to, and be seen by all, in the clouds of heaven, and not in deserts and secret chambers: nor of his spiritual coming in the more sudden, and clear, and powerful preaching of the Gospel all over the Gentile world; for this was to be done before the destruction of Jerusalem:

but of his coming in his wrath and vengeance to destroy that people, their nation, city, and temple: so that after this to look for the Messiah in a desert, or secret chamber, must argue great stupidity and blindness; when his coming was as sudden, visible, powerful, and general, to the destruction of that nation, as the lightning that comes from the east, and, in a moment, shines to the west.