Albert Barnes Commentary Micah 5:3

"Therefore will he give them up, until the time that she who travaileth hath brought forth: then the residue of his brethren shall return unto the children of Israel." — Micah 5:3 (ASV)

Therefore—since God has so appointed both to punish and to redeem, He—God, or the Ruler whose goings forth have been from of old from everlasting, who is God with God—shall give them up; that is, withdraw His protection and the nearness of His Presence, giving them up:

1. Into the hands of their enemies. Indeed, the far greater part never returned from the captivity but remained, although willingly, in the enemy’s land, outwardly shut out from the land of promise and the hope of their fathers (as in 2 Chronicles 36:17).
2. But also, all were, more than before, given up (Acts 7:42; Romans 1:24, 1:26, 1:28) to follow their own ways.

God was less visibly present among them. Prophecy ceased soon after the return from the captivity, and many tokens of the nearness of God and means of His communications with them—the Ark and the Urim and Thummim—were gone. It was a time of pause and waiting, in which the fullness of God’s gifts was withdrawn, so that they might look to Him who was to come. Until the time that she which travaileth hath brought forth—that is, until the Virgin who should conceive and bear a Son and call His Name Emmanuel, God with us, shall give birth to Him who shall save them. And then there shall be redemption, joy, and assured peace. God provides against the fainting of hearts in the long time before our Lord should come.

Then—(And). There is no precise mark of time such as our word 'then' expresses. He speaks generally of what should happen after the birth of the Redeemer. The remnant of His brethren shall return unto the children of Israel.

“The children of Israel” are the true Israel, Israelites indeed (John 1:47); they who are such, not in name (Romans 9:6, etc.) only, but indeed and in truth.

His brethren are plainly the brethren of the Christ: either because Jesus condescended to be born of the seed of David according to the flesh (Romans 1:3), and of them, as concerning the flesh Christ came, who is over all, God blessed forever (Romans 9:5); or as such as He makes and accounts them, and is not ashamed to call, brethren (Hebrews 2:11), being sons of God by grace, as He is the Son of God by nature.

As He says, Whosoever shall do the will of My Father which is in Heaven, the same is My brother and sister and mother (Matthew 12:50); and, My brethren are these who hear the word of God and do it (Luke 8:21).

The residue of these, the prophet says, shall return to be joined with the children of Israel; as Malachi prophesies, He shall bring back the heart of the fathers to the children, and the heart of the children to the fathers (Malachi 3:24, Hebrew). In the first sense, Micah foretells the continual inflow of the Jews to that true Israel who would first be called. All in each generation who are the true Israel shall be converted, made one in Christ, and saved.

So, whereas since Solomon all had been discord, and at last the Jews were scattered abroad everywhere, all, in the true Prince of Peace, shall be one (Isaiah 11:10, etc.). This has been fulfilled in each generation since our Lord came, and shall be still further fulfilled in the end, when they shall hasten and pour into the Church, and so all Israel shall be saved (Romans 11:26).

But “the promise of God was not only to Israel after the flesh, but to all” also that were afar off, even as many as the Lord our God should call (Acts 2:39). All these may be called the remnant of His brethren, even those that were formerly aliens from the commonwealth of Israel and afar off (Ephesians 2:12–14), but now, in Christ Jesus, made one with them—all brethren among themselves and to Christ their ruler.

“Having taken on Him their nature in the flesh, He is not ashamed to call them so,” as the Apostle speaks, confirming it out of the Psalm, where in the Person of Christ he says, I will declare Thy name unto My brethren (Psalms 22:22). There is no reason to take the name brethren here in a narrower sense than to comprehend all the remnant whom the Lord shall call (Joel 2:32), whether Jews or Gentiles. The word “brethren” in its literal sense includes both, and, as to both, the words were fulfilled.