Jamieson, Fausset and Brown on Isaiah 49:20

20. children ... after ... other--rather, "the children of thy widowhood," that is, the children of whom thou hast been bereft during their dispersion in other lands (see on Is 47:8) [Maurer].

again--rather, "yet."

give place--rather, "stand close to me," namely, in order that we may be the more able to dwell in in the narrow place [Horsley]. Compare as to Israel's spiritual children, and the extension of the gospel sphere, Ro 15:19, 24; 2Co 10:14-16. But Is 49:22 (compare Is 66:20) shows that her literal children are primarily meant. Gesenius translates, "Make room."