The Messiah represents Israel

In Isaiah, Messiah, the individual person, stands for Israel, Jacob, David, the vine/vineyard, the light, the way (of the Lord), Jerusalem, Zion, the Temple, etc.

He fills up all these designations. Messiah and his body (the Jew first and also the Gentile) The true Vine/Vineyard of the Lord spoken of in Isaiah ch.5., The New Jerusalem rebuilt by the Lord, The Temple (Isaiah and Revelation), The true and living Way (as used in Acts to distinguish the Jews who received Messiah from those
who said they were Jews but in one sense were not).

I don't think understanding Isaiah is all about something called "Replacement Theology." Men love religious entitlement, while God looks for true worshippers. "Replacement Theology" seems to be about replacing one abused religious entitlement with another abused religious entitlement; that is, bloodline and circumcision, some would say, are replaced with Christendom and infant sprinkling or baptism. But Jesus Christ, the faithful one, saves His people from their sins. And the legitimate are those who recieve Him and thereby gain union with Him. To those who recieved Jesus, "He gave the right to BECOME (not, "the right to claim an entitlement of being," but "the right to become") the Children of God. Man wants to stand up and take control of entitlement and God keeps telling man to sit down in humility before God and fellow man and HE will raise up the temple. HE will rebuild Jerusalem, HE will Make the mountain of the Lord from the stone cut out without hands. HE will declare to us who is the ONE with whom He is pleased. We do not have entitlement nor are we in control of doling out entitlement to others, not with our artificial laws, nor with our artificial ecclesiastical structures or priestcraft. Come to Jesus and God will not hide himself from you.

The Gospel is an announcement to the Jew first and also to the Gentile to come be found faithful in the faithful one. Recieve Him, and to those who recieve Him, God has granted the right to become the Children of God. The LORD will do it and it will be marvelous in our eyes. Don't say to yourselves we have Abraham for our father, for God is able to raise up children to Abraham from these stones.

As we noted in an earlier entry, the role of an explicit-predictive-element in prophecy/fulfillment is that it might be a sign post pointing the would be observant ones to the whole filling up accomplished through Christ. This is why when Paul spoke to the Jewish brothers he didn't record a list of prophecy/fulfillment prooftexts, as many of us have become used to seeing added to our Bibles, but rather He spoke of the necessity of bowing to the fact that Jesus filled up the meaning of all that was written in the Law and the Prophets.

If the whole filling up is accomplished through Jesus Christ then we might reasonably ask "what remains?" We allow the one who fulfills all to answer this for us.

"I go to prepare a place for you."
"But when you give a reception, invite the poor, the crippled, the lame, the blind, and you will be blessed, since they do not have the means to repay you; for you will be repaid at the resurrection of the righteous."
"Make disciples, teaching them to obey all that I have taught you."
"...You are to be my witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth."

For the early, Jewish, body of Christ there was no distinction being made between literal and figurative fulfillment of Isaiah because for a Jew moved by the Lord, like Paul for example, the irrefutable fact was that Jesus the messiah filled up all in all.

Is it ok with us that God speaks of the descendants of Jacob in the singular, that He calls them Israel...a name given to Jacob, and even in the singular as My son? It should be.

Exodus 4:22 "Then you shall say to Pharaoh, 'Thus says the LORD, "Israel is My son, My firstborn."

Hosea 11:1 When Israel was a youth I loved him, And out of Egypt I called My son.

Matthew 2:14-15 So Joseph got up and took the Child and His mother while it was still night, and left for Egypt. (15) He remained there until the death of Herod. This was to fulfill (fill up) what had been spoken by the Lord through the prophet: "OUT OF EGYPT I CALLED MY SON."

Jesus fills up, represents, and is Israel, the Son of God and the Servant of God.