As Christians, what should our attitude towards the Jews be? Asking this question will bring in some very diverse answers. Sadly, Christianity has a long and muddy history with anti-semitism. Some Church "Fathers" were very anti-semitic. Justin Martyr, for example, taught that circumcision and the observance of the Sabbath were marks God imposed on Jews to distinguish them from other nations, and from Christians. They were not alone. Even Martin Luther was rather famously anti-semitic, claiming that though many thought he was being too cruel to Jews, he actually wasn't cruel enough.
But the Bible simply does not allow for anti-semitism. This is to be expected from a Jewish book, but apparently, it does still need to be pointed out. The truth is, God will not cast off His people, whom He foreknew. Yes it's true, many Jews have rejected the Messiah, even to this very day. But it is also true that the remnant believes, and that God has made some very clear statements about even those who do not.
The truth is, we gentile Christians are the foreign branch grafted in to the promise. God can cut off and graft in whom He likes, but the point is, we as gentiles are grafted in. And God makes it quite clear that He can cut us off as easily as the natural branches. If God can condemn a Jew, He can condemn a gentile. We are not special just because many Jews reject Jesus, just as they are not special just because they descended from Abraham.
Ultimately, God tells us that He is our peace, having made both Jew and Gentile one, breaking down the middle wall of separation. Through the cross, both Jew and gentile are reconciled to God as one people. Anti-semitism has no place in Christianity.