The Messiah, Jesus, will not be the Messiah just of the Gentiles, or just of the Jews, but will be the Messiah King of the entire earth:
Pulpit Commentary: THE JEWS AND GENTILES SHALL BE GATHERED TOGETHER INTO MESSIAH'S KINGDOM. It is characteristic of "the evangelical prophet" that he dwells earnestly and frequently on the calling of the Gentiles (see Isaiah 2:2; Isaiah 19:22-25; Isaiah 25:6; Isaiah 27:13, etc.). The prophecies to Abraham had repeatedly declared that "in him," or "in his seed," "all the families of the earth should be blessed" (Genesis 12:3; Genesis 18:18; Genesis 22:18; Genesis 26:4); and some of the psalmists had echoed the glad sound and spoken of God as worshipped generally by "the nations" (Psalm 117:1; Psalm 148:11). But the idea had taken little hold upon the chosen people generally; and was practically new to them when Isaiah was inspired to preach it afresh. To render it the more palatable, he unites with it the promise of a great gathering of the dispersed Israelites from all quarters to the banner of Messiah, when it is set up. Verse 10.