Matthew 24:30

“And then will appear the sign of the Son of man in heaven, and then will all the tribes of the earth mourn, and they will see the Son of man coming on the clouds of heaven with power and great glory.”

And then the great sign will be seen, the sign of the Son of Man in Heaven, Compare Acts 7:55 where precisely the same sign, more secretly given, was to be an encouragement to the new-born church. And when they see this sign all the tribes of the earth will mourn, because the One whom they have rejected has now come to be their judge (compare Revelation 1:7). These ‘tribes of the earth', representing the people of earth (compare ‘those who dwell on earth' which occurs regularly in Revelation), may be seen as in deliberate contrast with ‘the twelve tribes of Israel' who represent the believing people of God (Matthew 19:28; James 1:1; Revelation 7:1) who are joyfully looking for His coming.

Some see ‘the sign' as signifying the raising of some kind of banner which will announce His coming, in line with Isaiah 11:10; Isaiah 11:12 (it is followed by the trumpet in Matthew 24:31). There the ‘root of Jesse (and thus of David) -- stands for an ensign of the peoples to whom the nations seek and His resting place will be glory'. Thus the Son of Man will be like a standard raised so that His people from among all nations may to gather to it, in order to share His glory.

‘Then will all the tribes of the earth mourn.' Compare Revelation 1:7, ‘behold He comes with the clouds, and every eye will see Him, and they who pierced Him, and all the tribes of the earth will mourn over Him.' The idea would appear to be of sorrow and anguish because they had failed to acknowledge Him before it was too late (similar to the weeping and gnashing of teeth elsewhere).

This would appear to have in mind Zechariah 12:10, ‘and I will pour on the house of David and on the inhabitants of Jerusalem the spirit of grace and of supplication, and they will look on Me Who they have pierced, and they will mourn for Him as one mourns for his only son, and be in bitterness for him as one who is in bitterness for his firstborn.' This is then followed in Zechariah 13:1 by a fountain opened for sin and uncleanness. If that be the case there may here be a hint of hope for last minute repentance, but Zechariah 12:10 to Zechariah 13:1 more probably refers primarily to the coming of the Holy Spirit and its results (Acts 2), so that Jesus' idea here may rather be of a contrast between that appearance and this one at the end when that hope has gone, and all that awaits is bitterness of soul at what they have lost.

Then they will see the Son of man coming on the clouds of heaven with power and great glory. The kingship, power and glory given to Him at His resurrection (Matthew 28:18; Acts 2:36; Daniel 7:13), and initially demonstrated in the activities of the early church (Matthew 16:28; Matthew 26:64; Mark 9:1; Luke 9:27; Acts 7:55), will be revealed to all at His glorious appearing (Matthew 16:27; Mat 25:31; 2 Thessalonians 1:7; Titus 2:13). ‘Coming on the clouds of Heaven' signifies His heavenly nature and power, and the power and great glory stress that He has come as judge (compare Matthew 25:31). Thus for His own there will be joy, and for others bitterness of soul.