Albert Barnes Commentary Joel 2:27

"And ye shall know that I am in the midst of Israel, and that I am Jehovah your God, and there is none else; and my people shall never be put to shame." — Joel 2:27 (ASV)

And you shall know that I am in the midst of Israel - God had foretold their rebellion and His forsaking them, "the troubles" which would "find" them, and that they would say, Are not these evils come upon us, because our God is not among us? (Deuteronomy 31:17). It had been the mockery of the pagans in their distress, Where is their God? (Joel 2:17).

"Now, by the fulfillment of His promises and by all God’s benefits, they would know that He was among them by special grace as His own peculiar people." Still more was this to be fulfilled for Christians, in whose hearts He dwells by love and grace, and of whom He says, Where two or three are gathered together in My name, there will I be in the midst of them.

In the highest sense, God was in the midst of them, in that "God the Son, equal to God the Father regarding His Godhead, did, in the truth of human nature, take our flesh." To see and know this is glory and bliss ineffable.

Therefore He repeats, and by repeating, confirms what He had said, And My people shall never be ashamed. Indeed, glorious, magnified, honored, shall be the people to whom such a Son was promised, and of whom He was born. "Glorious to them is that which the Apostle says, that He took not on Him the nature of Angels, but He took the seed of Abraham, and this glory shall be eternal."