Albert Barnes Commentary Zechariah 9:14

"And Jehovah shall be seen over them; and his arrow shall go forth as the lightning; and the Lord Jehovah will blow the trumpet, and will go with whirlwinds of the south." — Zechariah 9:14 (ASV)

And the Lord shall be seen over them – “He will reveal himself,” protecting them. Cyril: “He says plainly, that the Lord God will be with them and will fight in battle array with them and will with them subdue those who resist them.” It is as if he would say, When they go forth and preach everywhere, the Lord shall work with them and confirm the word with signs following (Mark 16:20). And His arrow shall go forth as the lightning. Habakkuk directly calls the lightnings the arrows of God: at the light of Your arrows they went. Here it is probably of an invisible agency, and so compared to that awe-inspiring symbol of His presence, the lightning.

And the Lord God shall blow with the trumpet – As their Commander, directing their ways. The blowing of the trumpet by the priests in war was commanded, to bring them to remembrance before God: If you go to war in your land against the enemy that oppresses you, then you shall blow an alarm with the trumpets, and you shall be remembered before the Lord your God, and you shall be saved from your enemies (Numbers 10:9). Abijah said, God Himself is with us for our captain, and His priests with sounding trumpets to cry alarm against you (2 Chronicles 13:12).

And shall go with whirlwinds of the south – As being the most vehement and destructive. So Isaiah, As whirlwinds in the south sweep by, He comes from a desert, from a terrible land (Isaiah 21:1). Such whirlwinds struck the four corners of the house where Job’s children were, and they perished.