No, there's no division in the promises - as JGR is pointing out. Jesus IS the true Israel.
Quoting Kim Riddlebarger:
In Isaiah 41:8-9, the prophet spoke of a future restoration of Israel in these terms. “But you, Israel, my servant, Jacob, whom I have chosen, the offspring of Abraham, my friend; you whom I took from the ends of the earth, and called from its farthest corners, saying to you, `You are my servant, I have chosen you and not cast you off.'” The same promise is reiterated in the next chapter of Isaiah (42:1-7), when the LORD declares of his servant, “I am the Lord; I have called you in righteousness; I will take you by the hand and keep you; I will give you as a covenant for the people, a light for the nations”( v. 6). Isaiah continues to speak of this servant in chapters 44 (vv. 1-2) and 45 (v. 4).
Dispensationalists, given their so-called "literal hermeneutic," are bound to interpret such passages literally, thereby assign the fulfillment of these prophecies of Isaiah to a future earthly millennium in which Israel co-exists with Gentiles under the reign of the Davidic king (See Walvoord,
The Millennial Kingdom, 302-304; and Pentecost,
Things to Come, 503-508). In effect, this amounts to the restoration of the monarchy as Jesus takes his place on David's royal throne and rules the nations from this restored Israel.
But is this how the New Testament interprets these messianic prophecies regarding the servant of the Lord? Who is this servant of the Lord? It is the nation of Israel, or is it Jesus, Israel’s Messiah?
In order to answer this questions, we must see that the gospel writers interpret these prophecies from Isaiah as fulfilled in the messianic mission of Jesus.
First, in Matthew 12:15-21, for example, when Jesus withdrew from the crowds who had followed him, Matthew reports that this event fulfilled what had been spoken in Isaiah the prophet. This event serves to demonstrate that Jesus is the true servant of the Lord.
Second, as Jesus cast out demons and healed the sick, Matthew saw in this the fulfillment of Isaiah’s prophecies of a suffering servant who would take upon himself our infirmities and carry our diseases (Matthew 8:17 with Isaiah 53:4).
Third, in Luke’s gospel, Luke speaks of both Israel (cf. Luke 1:54) and David as the servant of God (Luke 1:69). Yet in Acts, Luke pointedly speaks of Jesus as the servant of God (Acts 3:13). After his crucifixion, God raised Jesus from the dead so that people everywhere might be called to repentance (3:26).
Fourth, when the Ethiopian eunuch hears a reading from
Isaiah 53:7-8 and asks Philip about whom this prophecy refers, Luke tells us that Philip informed the Ethiopian that this passage does indeed
refer to Jesus (Acts 8:34-35).
But this is not all that is in view here. In Hosea 11:1, Hosea predicted a time when “Israel was a child, I loved him, and out of Egypt I called my son.” But in Matthew 2:15, the evangelist tells us that Hosea’s prophecy was fulfilled when his parents took Jesus to Egypt to protect him from Herod’s “slaughter of the innocents” (Matthew 2:3-18). Yet, after Herod had died, God called Jesus and his family to return to Nazareth. Matthew takes a passage from Hosea, which clearly refers to Israel, and tells his reader that this passage is now fulfilled in Jesus Christ!
He does this to prove to his largely Jewish audience that Jesus is the servant of the Lord, foretold throughout the Old Testament (especially Isaiah).
By now it should be clear that according to many New Testament writers,
Jesus is the true servant, the true son and the true Israel of God. Recall too that it was Isaiah who spoke of Israel and the descendants of Abraham as the people of God. It as through the seed of Abraham that the nations of the earth would be blessed.
Therefore,
even as Jesus is the true Israel, he is the true seed of Abraham. This is the point that Paul is making in Galatians 3:7-8, when he says “know then that it is those of faith who are the sons of Abraham. And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, `
In you shall all the nations be blessed.'” ~ Riddleblog - The Latest Post - Amillennialism 101 -- Jesus Christ: The True Israel