God says the calamity to come will not be permanent. For the period of misery that is to come will be limited; it will come to an end. Until the time when she who is in labor has given birth…his brothers (i.e., the people of Judah) shall return to the people of Israel.
When the child is born, the misery stops. That child will save the people from destruction.
Micah foretells that a saviour will come and that the people will return from exile to their own land. Then the rest of his brothers (that is, the exiles) shall return to the people of Israel.
The exile lasted at least seventy years and the Israelites who were taken captive to Babylon at the beginning of the captivity would no longer have been alive. The Israelites would then return to the people of Israel,
that is, returning to their own land. You could think of King Cyrus who let the people go out of exile and who gave permission to return to the homeland (see 2 Chronicles 36:22–23). Yet Micah would not have referred to this king, for Cyrus was not born in Bethlehem. The prophecy of Micah is first and foremost about the deliverance from exile, but it also goes much further: the Messiah is born. And he is the all-encompassing deliverer.
3 Therefore he shall give them up until the time when she who is in labor has given birth; then the rest of his brothers shall return to the people of Israel.