49:18-23 Zion is addressed as an afflicted widow, bereaved of her children. Numbers flock to her, and she is assured that they come to be a comfort to her. There are times when the church is desolate and few in number; yet its desolations shall not last for ever, and God will repair them. God can raise up friends for returning Israelites, even among Gentiles. They shall bring their children, and make them thy children. Let all deal tenderly and carefully with young converts and beginners in religion. Princes shall protect the church. It shall appear that God is the sovereign Lord of all. And those who in the exercise of faith, hope, and patience, wait on God for the fulfilment of his promises, shall never be confounded.
21. Who, &c.—Zion's joyful wonder at the unexpected restoration of the ten tribes. Secondarily, the accession of spiritual Israelites to the mother church of Jerusalem from the Gentiles is meant. This created surprise at first (Ac 10:45; 14:27; 15:3, 4).
lost … am desolate, a captive, and removing to and fro—rather, "bereaved of … have been barren, an exile and outcast" [Horsley]. She had been "put away" by Jehovah, her husband (Isa 50:1); hence her wonder at the children begotten to her.