Jamieson, Fausset and Brown on Isaiah 49:6

6. It is a light thing--"It is too little that Thou shouldest," [Hengstenberg], that is, It is not enough honor to Thee to raise up Jacob and Israel, but I design for Thee more, namely, that Thou shouldest be the means of enlightening the Gentiles (Is 42:6, 7; 60:3).

the preserved--namely, those remaining after the judgments of God on the nation--the elect remnant of Israel reserved for mercy. Lowth, with a slight but needless change of the Hebrew, translates for "tribes" and "preserved," the "scions"--the "branches."