Michael Hansen recently wrote about how Christ is the new Israel. This point cannot be stressed enough when discussing with the theology of dispensationalism. Sam Storm's book Kingdom Come spends almost too much time unraveling false theologies about Israel but the opening chapters are a gem. I cannot really add to the fundamental arguments. But I can provide an extra text that is uniquely qualified to show that Jesus Christ is the only true Israelite and the new Israel.

This will keep us away from talks of "supersessionism." Let me be clear, it is not accurate language to say "the church has replaced Israel." The Old Testament prophecies for Israel were all found fulfilled in Jesus Christ. As Christ's body the church participates but only as directly related to Christ. The church has not replaced Israel. Christ is the fulfillment of everything pertaining to Israel and we are just along for the ride. Michael correctly pointed to Hosea 11:1 as a prime example of this since Matthew's gospel utilizes this prophecy. However, Hosea has an even greater prophecy that points towards Christ,

“Come, let us return to the Lord;
    for he has torn us, that he may heal us;
    he has struck us down, and he will bind us up.
2 After two days he will revive us;
    on the third day he will raise us up,
    that we may live before him. - Hosea 6:1-2

As the astute reader of the Bible will know, this verse is never quoted in the New Testament. The reasons for that are beyond my pay grade so do not ask. Hosea's passage depicts the return of Israel from exile. And much like Hosea 11, this passage finds its fulfillment in Jesus Christ's death, burial, and resurrection. Christ's resurrection (the thing Paul ties the gospel to 1 Cor 15) is prophetically for Israel. Everything else theologically is tied to this. Christ's resurrection is the great work of God that establishes Christ's authority and founds the church (Eph 1:19-23). Our salvation mimic this great work always "in him [Jesus]" (Eph 2:5-8). The gospel is that Israel has been resurrected in Jesus Christ. The church [literally ekklesia ] is the new "congregation of Israel" in Him.

It is Christ's resurrection that puts to death God's covenant with national Israel. God's covenants with Abraham, Moses, and David find themselves fulfilled in the cross (Eph 2:12-16). Christ is the new Adam. He is the firstfruits of new creation. There are no remaining promises for Israel outside of Jesus Christ since He alone fulfills the prophetic resurrection.