Albert Barnes Commentary Joel 3:11

"Haste ye, and come, all ye nations round about, and gather yourselves together: thither cause thy mighty ones to come down, O Jehovah." — Joel 3:11 (ASV)

Once more all the enemies of God are summoned together. Assemble yourselves, (Others in the same sense render, “Haste ye,”) and come, all ye pagan, round about, literally “from round about,” that is, from every side, so as to surround and hem in the people of God. Then, when the net had been, as it were, drawn closer and closer around them, and no way of escape is left, the prophet prays God to send His aid: thither cause Thy mighty ones to come down, O Lord.

Against “the mighty ones” of the earth, or “the weak” who “say” they are “mighty” (the same word is used throughout), there “come down the mighty ones of God.”

The “mighty ones of God,” whom He is prayed to “cause to come down,” that is, from heaven, can be no other than the mighty angels, of whom it is said, they are mighty in strength (Psalms 103:20) (still the same word), to whom God gives charge over His own, to keep them in all their ways (Psalms 91:11), and one of whom, in this place, killed one hundred and fourscore and five thousand (2 Kings 19:35) of the Assyrians.

So our Lord says, The Son of man shall send forth His Angels, and they shall gather out of His kingdom all things that offend, and them that do iniquity (Matthew 13:41).