I've been reading the Holy Father's new book Jesus of Nazareth. It is excellent.
He relies heavily on Rabbi Neusner's A Rabbi Talks with Jesus, a book a read in seminary years ago.
Rabbi Neusner objects to the Christ's of claims, primarily because Jesus presents himself as a new Lawgiver, like Moses. In fact, Neusner observes that Christ assumes that he is in fact "Torah" or "Law". Christ basically assumes that he is the Law - a theme that the Apostle Paul (previously Rabbi Saul) picked up when he said that Christ is the end of the Law for those who believe (cf. Rom 10:4)
The difficulty that Christians have is justifying to our Jewish brethren the reason for our "abandonment" of the what St Thomas Aquinas called denoted as the ceremonial and civil laws.
Pope Benedict XVI rightly explains that the universalizing nature of Christ's death requires that the particular laws pertaining to Israel cannot be universalized. It is the Theonomist error to believe that the Mosaic Covenant is the standard for Gentile nations.
The ceremonial/civic laws of Israel were instituted so that Israel would remain distinct and thus be a kingdom of priests to minister to all nations. The Temple was supposed to be a "house of prayer for all nations"(Is 56:7).
The death of Christ therefore universalizes the moral law of God (to love God and our neighbor) and the resurrection reveals the new locus of prayer, the new Temple - the Body of Christ.
The sacramental/ceremonial dimension of Israel is preserved in the incarnate "Body of Christ." The faithful enter this Temple by initiation into the Church (the "Body of Christ") and this initiation is priestly and thus sacramental.
The stumbling block for Rabbi Neusner and other observant Jews is that Christ universalized the mission of Israel in his very Person. God made all people and wants to know all people - not merely the circumcised ones. The divine vocation and goal of Israel was not to make everyone ethnically Jewish (God could have done that). The goal was to be "a light to lighten the Gentiles."