Then shall appear the sign of the Son of man. — Can we picture to ourselves what this sign shall be? Is it distinct from the coming of the Son of Man which here is so closely united with it? Men have given wildly conjectural answers to these questions, and have dreamt of the cross as appearing in the sky (as if the vision of Constantine were to be reproduced in the last days), or the lightning flash that shall dazzle all men with its brightness, or of some visible manifestation which none can imagine till it shall come. The vision of Daniel 7:13 supplies, it is believed, the true answer. The sign of the Son of Man is none other than the presence of the Son of Man Himself, coming in the clouds of heaven, in the ineffable glory of His majesty. And here, too, we must remember that we are still in the region of apocalyptic symbols. All such imagery falls short of the ultimate reality, and a “sign in heaven” is something more than a visible appearance in the sky.
Then shall all the tribes of the earth. — It lies in the nature of the case, that the “tribes” are those who have done evil, and who therefore dread the coming of the Judge. The words find their best comment in Revelation 1:7, where St. John combines them freely with the prediction of Zechariah 12:10, “They also which pierced Him,” obviously including not only those who were sharers in the actual “piercing” of the crucified body of the Lord Jesus (John 19:37), but all who in any age “crucify the Son of God afresh” (Hebrews 6:6).