Israel and Israel
In Hebrews 12:26-27, the author of Hebrews climactically describes yet another reason why Jewish converts to Christianity should not go back to their old Judaism and the worship of the temple. God is in the process of shaking things up, of tearing down the old covenant temple—the one "which was made" — so that the new covenant temple, established through Jesus' own sacrifice, may remain. It is just one example of a ubiquitous theme that runs throughout the New Testament. While it has many current applications to Christian faithfulness, we shouldn't avoid its primary referent, namely the destruction of Jerusalem and the temple in 70 AD. God tore down the Old Covenant structures to establish, for all the nations, the New Covenant structures (which fulfill the old), namely the church, communion, and baptism reflecting the kingly, prophetic, and priestly work of Christ.
The destruction of Jerusalem is a fundamental theme in the Bible. It lay just under the surface of numerous New Testament texts and appears rather explicitly in others. For the authors of the New Testament, the events of 70 AD lay just ahead. While Jesus expressly spoke of it in the Olivet Discourse (Mark 13 and Matthew 24), later Paul, Peter, and John all make use of this prediction of judgment as further vindication of Jesus' claims to be the Son of Man and the Son of the Living God. The theme is so prominent that modern liberal scholars have used its presence in the New Testament as proof that these texts were written later than most of church history has thought. We can't have biblical authors accurately predicting historical events - that might imply that the Scriptures are, in fact, divinely inspired!
But the Biblical authors see this coming (in the future - for them) event as evidence. For here is an institution that has proven itself to be God's enemy by rejecting and crucifying God's Son. The destruction of Jerusalem and the temple is foretold explicitly by Jesus (Matthew 24). The author of Hebrews describes it in terms of the shaking of heaven and earth, as well as the removal of things that are made (Hebrews 12). John describes it as the destruction of the whore of Babylon (Revelation 19), whom the nations turn against in Revelation. We cannot forget that within decades of these things being written, Jerusalem and the Temple were destroyed by Titus and the Roman legions, and the Bible interprets this as the decisive act of God's judgment against Israel, which had rejected Him and the vindication of Jesus as Messiah and Lord.
What does any of this have to do with what Christians should think about the modern state of Israel specifically and the Jewish people generally? God made glorious promises to Abraham and his children. Jesus said that God could raise up children for Abraham from the stones. Paul tells us explicitly that the children of Abraham are all those who have faith like Abraham, believing in Jesus (Romans 4). He also tells us that the mark of circumcision that reveals the inheritors of those promises are those whose hearts have been circumcised - not the flesh (Romans 2:29). He tells us that being part of the tree of Israel is a matter of who is attached to Jesus by faith—Jew or Gentile alike (Romans 11). So, whatever promises we find given to Israel, Abraham, and his family, all of them belong to those who belong to Jesus. These promises include the land promises (which Paul says refer to the whole world, not just "the land" in Romans 4), the riches and glory of the nations (Haggai 2:6ff.), and peace with God. This is to say that all the promises belong to the church, which is the Israel of God. They cannot be claimed by anyone who rejects the Son of David; for everyone outside of Christ, there remains only the promise of judgment and wrath.
A modern theological system emerged in the late 19th century and gained popularity during the first half of the 20th century. Dispensationalism has gained increasing popularity in the United States over the past 80 years, primarily due to the widespread influence of the Ryrie Study Bible, the Left Behind Series, John MacArthur, and the growth of numerous seminaries that subscribe to its tenets. While there is some diversity in the Dispensational camp regarding several issues. It, in all its forms, fundamentally denies that the promises given to Abraham are given to all those in Jesus. It maintains a pervasive ethnic division (contra Ephesians 2:14) in how God acts redemptively. Israel is always ethnic Israel. Gentiles are always Gentiles. This popular and innovative (and not in a good way) theology received a real kick in the pants with the formation of the state of Israel in 1948. All manner of speculative interpretations began to abound, and this was seen as the restoration of God's promises to God's people - ignoring the problem that this new Jewish State was still fundamentally in rebellion against her King. However, the American dispensational imagination was awakened. So current history became the stuff of prophetic fulfillment, with much debate about who exactly would be the Antichrist and how long until the rapture (ignoring the problem that the modern notions of the rapture are themselves historically novel). This coincided with international horror over the atrocities committed against European Jews during the Holocaust. (Good) International sympathy for the Jewish people combined with this novel American theology to produce a heady mix of ideas and a lot of political and theological confusion - which we have inherited in our day.
But the Israel of God is the church of Jesus Christ. She, in Jesus, has inherited all the promises of God. In Jesus, and only in Jesus, do the promises of God find their 'amen.' So, following from this assertion, we should make the following theo-political observations:
1) Unbelieving Jews have no claims to the promises of God given to Israel. In maintaining their rebellion against God's Son and the King of all nations, they have forfeited those promises and proven themselves to not belong to God's Israel. In this sense, they are no different than unbelieving Brits, Chinese, or Germans. Outside of Christ, no one has any claims on the promises of God outside of His judgment.
2) The State of Israel is an ethno-state - meaning that citizenship in the State of Israel is dependent on being of a particular ethnicity. This makes Israel unique among the nations of the world (Japan may functionally come close.) Oddly enough, such a policy would be condemned by most Western countries in the West itself but is not condemned in Israel. There are historical reasons for this (notably, the Holocaust). However, I should note that there is nothing morally problematic with this policy on its own.
3) Given #'s 1 & 2, the State of Israel should not be confused with the Israel of God in Scripture. In this sense, Israel is not Israel. The Church is Israel, and the church comprises men and women from every ethnic group under heaven.
4) The State of Israel has a right to defend its borders and against its enemies, just as any nation-state has.
5) The United States may choose to support Israel or to oppose Israel according to its own interests, but it is under no "theological" obligation to support the State of Israel. The clear statements in Scripture regarding the treatment of Israel by the nations are clearly interpreted in the New Testament to be fulfilled in how the nations treat the church. The book of Revelation is, itself, largely a prophetic description of God's judgment of the nations and the Jewish people explicitly for their mistreatment of the early church.
6) The publicly stated goal of the leaders of nearly all of Israel's neighbors is to annihilate Israel and take over their land. This isn't simply a matter of over-heated political rhetoric. It has been historically demonstrated over the past 80 years through military and terrorist attacks against Israel's military and civilian populations. Whatever moral judgments are to be made concerning Israel's behavior in the region must take this ongoing reality.
7) Islam, since its inception, has been at war with the Christian West. It is actually in the Koran. It, like Christianity, has world-conquering ambitions. The Crusades, no matter what you learned in school, began as a defensive war by the Christian West to push back the invasion of Islam into Europe and as a reaction to the enslavement, torture, and execution of Christians in the lands Islam had conquered.
8) A significant number of theologians throughout church history have seen in texts like Romans 11 the hope of a great revival among the Jewish people, wherein they repent of their rebellion against God and turn to trust in Christ, and thus are grafted back into the Israel of God. (For an excellent book promoting this interpretation, see *The Puritan Hope* by Iain Murray). Whether one follows this interpretation or not, it is a thing we ought to pray for and work towards, not simply among the Jews but among all the peoples of the earth.
In conclusion, if you are in Christ, then all the promises given to Abraham and to Israel throughout the whole of Scripture are yours. You are a part of the Israel of God. The past judgments of Israel, especially the terrible judgments of 70 AD, should not give rise to boasting and arrogance against the Jewish people. In Romans 11, Paul explicitly warns against this danger, and he doesn't warn against such things because they aren't likely to happen. They should drive you towards humility and a renewed commitment to work out your salvation with fear and trembling, lest you, too, fall. Do not discount the fullness of Christ's work on our behalf. His life, death, resurrection, and ascension have secured for us the hope of glory, and all the promises of God are, in him, yes and amen.