John Lightfoot on Matthew 24:30

[And then shall appear the sign of the Son of man.] Then shall the Son of man give a proof of himself, whom they would not before acknowledge: as proof, indeed, not in any visible figure, but in vengeance and judgment so visible, that all the tribes of the earth shall be forced to acknowledge him the avenger. The Jews would not know him: now they shall now him, whether they will or no, Isaiah 26:11. Many times they asked of him a sign: now a sign shall appear, that he is the true Messias, whom they despised, derided, and crucified, namely, his signal vengeance and fury, such as never any nation felt from the first foundations of the world.