The answer to this dilemma is in that there are two Israels. The one of earth and one of heaven. Same with Jerusalem that is above vs. the one that is for this current age. (see Galatians 4:25-27 for Jerusalem that is of heaven vs earthly Jerusalem)
Abraham was promised his seed would be as the "sand on the seashore" and the "stars of heaven". So you can see a twofold promise. One of earth and one is heavenly.
Flesh and blood cannot inherit the kingdom of God. The Israel that is of heaven began when Jesus rose from the dead. This Jesus is the "head" of the body that is heavenly Israel.
You'll notice that Jesus is Israel by comparing what you know of Jesus with the following passages:
- Jesus is called out of Egypt and is said to fulfill the prophecy only for Israel the Son of God.
Hosea 11:1
When
Israel was a child, then I loved him, and called my son out of Egypt.
Matthew 2:15
And was there until the death of Herod: that it might be fulfilled which was spoken of the Lord by the prophet, saying, Out of Egypt have I called my son.
- Israel is the only firstborn Son of God.
Exodus 4:22
And thou shalt say unto Pharaoh, Thus saith the Lord,
Israel is my son, even my firstborn:
John 3:16 For God so loved the world, that
he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
Colossians 1:18
And he is the head of the body, the church: who is the beginning,
the firstborn from the dead; that in all things he might have the preeminence.
Finally, Isaiah 49:1-6 is about Jesus. Yet, is called "Israel". The description is of Jesus as we read in Revelation He has a "sharp two edged sword" coming out of His mouth. (Revelation 1:16)
And the most clear point that this is about Jesus rather than the earthly nation of Israel is because it says of Him that He was formed to "bring Jacob again to him" and it says of them "though Israel be not gathered" yet shall I(Jesus) be glorious in the eyes of the Lord ..."
So, both Jesus is called Israel here and the earthly nation whose head is Jacob is called Israel also. That's why there can be confusion on this topic. But all confusion should be cleared up when we realize that there is a distinction between the earthly Israel and the heavenly Israel. The heavenly Israel begins when Jesus rises from the dead. The reason for this is because He at that point became immortal and overcame death. So all who are born as members of His body share in this immortality and they become members of the eternal Israel rather than the temporal, earthly Israel.
Isaiah 49:1-6
49 Listen, O isles, unto me; and hearken, ye people, from far; The Lord hath called me from the womb; from the bowels of my mother hath he made mention of my name.
2 And he hath made my mouth like a sharp sword; in the shadow of his hand hath he hid me, and made me a polished shaft; in his quiver hath he hid me;
3 And said unto me, Thou art my servant,
O Israel, in whom I will be glorified.
4 Then I said, I have laboured in vain, I have spent my strength for nought, and in vain: yet surely my judgment is with the Lord, and my work with my God.
5 And now, saith the Lord that formed me from the womb to be his servant, to bring Jacob again to him, Though Israel be not gathered, yet shall I be glorious in the eyes of the Lord, and my God shall be my strength.
6 And he said, It is a light thing that thou shouldest be my servant to raise up the tribes of Jacob, and to restore the preserved of Israel: I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth.