Dave, I totally understand what you are getting at. Because double meanings exist in prophecy, it is easy to not understand.
What you are saying is that the name "Israel" applies to Messiah as well as to Jacob and his genetic offspring called the nation of Israel.
I had this realization in reading the book of Isaiah. In these verses, it can be read either way.
Isa_41:8 But thou, Israel, art my servant, Jacob whom I have chosen, the seed of Abraham my friend.
The natural reading of the verse is taken as meaning the sons of Jacob. But the wording of "the seed of Abraham my friend" hearkens unto Galatians.
Gal_3:16 Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
While Strong's does not give us the Hebrew text completely, "seed" in the Hebrew text is
zerah is singular, not the plural
zerim.
Consequently, Paul makes this conclusion in Galatians.
Gal 3:29 And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
Logically, then, the body of Christ is the Israel of God. Of course, Christian Zionists and Messianic Jews get upset because it means the church has replaced Israel. Gads, not replacement theology!
Well, the promises of God that are unconditional from God to national Israel, will not be replaced, but the conditional promises of the Mosaic covenant has been replaced. Get over it people.
Apart from Replacement theology, the difficulty in accepting Israel as another name for the Messiah comes from not really understanding the divinity and humanity of the Messiah. We say he was fully God and fully man with his divinity limited so he could walk as a man.
But understanding his humanity is helpful in understanding our justification. We are not justified by the choices of God, but by the choices of the man Jesus Christ. If the fullness of God dwelt in him bodily, one must assume that meant the trinity of Father, Word, and Holy Spirit. However, while the fullness of God dwelt in the man, it was the Word that became a man, not the Father nor the Spirit.
And as a man, Jesus had a created human spirit, soul, and body. Paul tells us that it was the man Christ Jesus who justified us.
Rom 5:18 Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life.
Rom 5:19 For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous.
In my opinion, when the sins of the world were placed on Jesus, and he cried out, My God why have you forsaken me? The fullness of God left Jesus, and as a man he became sin who knew no sin, justifying us.
In my opinion, the holiness of God is his immutable protection from sin. As long as God remained in Jesus the man, sin could not touch Jesus. God had to leave Jesus, so he could become sin.
Jesus as a man was not in his glory when he walked the Earth. I think after he ascended to heaven in Acts 1 is when he was glorified. I think being glorified meant that his humanity became inseparable from his divinity. A metamorphosis of physical with spiritual. When we are glorified, this, too, shall happen to us.
And this is the point that I think is confusing regarding the divinity and humanity of Jesus during his incarnation. I think most people assume that his physical being was already merged with his divine being.
As will be expected, I have no doubt that I will be called a heretic for what I just wrote. That seems to be the default answer for all who see any variation on orthodoxy as being wrong in this forum. Well, I am not trying to create a cult. Just sharing my opinion.