Sky signs.
The figurative character of this verse is apparent. It does not describe actual events. It belongs to astrological rather than to astronomical associations. There is no literal interpretation of these words possible. Isaiah uses similar symbols in prophesying the Divine judgments on Babylon (Isaiah 13:10), and we may reasonably think that such a scriptural passage suggested our Lord's statement. "Even the common speech of men describes a time of tribulation as one in which 'the skies are dark,' and the 'sun of a nation's glory sets in gloom.'" The verse is plainly poetical and pictorial, but what it pictures is the series of terrible civil calamities and commotions and distresses which attended the Roman siege of Jerusalem. It is not necessary to suppose any allusion to a future breaking up of the framework of the earth in the last times. Of that no man really knows; and no precise description has been or could be given.
I. SKY SIGNS THAT TEACH GOD'S WORKING IN THE WORLD. Men might be disposed, even those disciples might be disposed, to look upon the events of the siege of Jerusalem as just ordinary national incidents. Jesus therefore used figures in relation to them which lifted them to a higher plane, and made the disciples think about them, discern their relation to the whole course of God's dealing with his ancient people, and trace his direct working in them. All the events connected with the history of the Jewish nation are designedly revelational; and it is their revelational value which disciples must be helped to discern. But when once we see that this is true for the Jewish nation, we begin to see that it is true for all nations. Men make much now of the "philosophy of history." They never can read history aright until they begin to study the "religion of history." Wars, migrations, changing dynasties, are not understood till they are seen to be "sky signs."
II. SKY SIGNS THAT TEACH GOD'S REDEMPTIVE PURPOSE FOR THE WORLD. Christ's way of referring to the overthrow of organized Judaism by the destruction of the sacred city fitted that historical fact into the Divine redemptive plan. It was the removing of the scaffolding, that the complete building might come into view. It was the withdrawal of dependence on material forms, in order that the spiritual reality might fully occupy men's minds and hearts.—R.T.