John Lightfoot on Matthew 24:27

[For as the lightning, &c.] To discover clearly the sense of this and the following clauses, those two things must be observed which we have formerly given notice of:--

1. That the destruction of Jerusalem is very frequently expressed in Scripture as if it were the destruction of the whole world, Deuteronomy 32:22; "A fire is kindled in mine anger, and shall burn unto the lowest hell" (the discourse there is about the wrath of God consuming that people; see verses 20,21), "and shall consume the earth with her increase, and set on fire the foundations of the mountains." Jeremiah 4:23; "I beheld the earth, and lo, it was without form and void; and the heavens, and they had no light," &c. The discourse there also is concerning the destruction of that nation, Isaiah 65:17; "Behold, I create new heavens and a new earth: and the former shall not be remembered," &c. And more passages of this sort among the prophets. According to this sense, Christ speaks in this place; and Peter speaks in his Second Epistle, third chapter; and John, in the sixth of the Revelation; and Paul, 2 Corinthians 5:17, &c.

2. That Christ's taking vengeance of that exceeding wicked nation is called Christ's "coming in glory," and his "coming in the clouds," Daniel 7. It is also called, "the day of the Lord." See Psalm 1:4; Malachi 3:1,2, &c.; Joel 2:31; Matthew 16:28; Revelation 1:7, &c. See what we have said on chapter 12:20; 19:28.

The meaning, therefore, of the words before us is this: "While they shall falsely say, that Christ is to be seen here or there: 'Behold, he is in the desert,' one shall say; another, 'Behold, he is in the secret chambers': he himself shall come, like lightning, with sudden and altogether unexpected vengeance: they shall meet him whom they could not find; they shall find him whom they sought, but quite another than what they looked for."