There are many remarkable and wonderful teachings of Jesus in the New Testament. However, they are the teachings of a human being, not a God, and many of them--including the most morally enlightened--are paralleled in rabbinic literature. One cannot truly understand Jesus without understanding the climate in which he grew up. When one studies the Talmud, the image of Jesus becomes sharper--and still very impressive--but less original.
Jesus' criticisms of the rabbis of his day are echoed in the literature of the prophets centuries before. When Hosea writes, "I desire mercy and not sacrifice" (Hosea 6:6), or Isaiah thunders, "I cannot endure sin coupled with solemn ceremonies (Isaiah 1:13), we are hearing the same themes Jesus so deftly expounded later on.
4. The idea of the Second Coming seems to have grown out of genuine disappointment. We are told in the Gospels, "Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom." When Jesus died, true believers had to theologically compensate for the disaster. It remains significant, I believe, that the vast majority of people who knew him did not see Jesus as divine. Unless the entire Jewish population of Jerusalem at the time was either wicked or foolish, they--who knew Jesus far better than we--did not respond to his presumed divinity because he was clearly human.
5. The history of Christianity is not such as would persuade Jews that Christians are in possession of a superior moral truth. The history is too long and painful to summarize here, but many good books are available that elaborate on what the historian Jules Isaac called "the teaching of contempt." The thousands, even millions, of innocents who lost their lives, their children, their hope, from a refusal to be other than they were make it difficult to see Christianity in its historical garb in anything but a dark, forbidding light.
6. Although many faiths, including some Roman mystery religions, spoke of a man/god, Judaism sought to keep clear the boundaries between the human and the divine. The blurring was taken to be the sign of betrayal of the tradition.
7. Jesus did place great emphasis on internal spirituality. This was not because he was more spiritually advanced, but because society was more advanced materially. Moses had to set up a system of courts, of civil and criminal law. Jesus was born in Rome, with the most advanced civil society of the time. He did not need to discuss external rites, either religious or civil. They were taken care of by Roman law and the developed Jewish law. In this sense, Islam bears a closer kinship to Judaism; it, too, is a religion of law, necessitated by Muhammad's melding desert tribes into a religious community, much in the manner of Moses. Hence, as Moses Montefiore said of Jesus, "Public justice is outside his purview."
8. The idea that one can be saved only through Jesus is contrary to simple compassion and justice. Judaism teaches that "the righteous of all nations have a share in the world to come." Maimonides writes in a letter that there are non-Jews who "bring their souls to perfection." That is the simple truth that all faiths should acknowledge and celebrate. Otherwise, there can be no kinship. As Abraham Joshua Heschel once wrote about attempts to convert the Jews: "How can we take seriously a friendship that is conditioned ultimately on the hope and expectation that the Jew will disappear? How would a Christian feel if we Jews were engaged in an effort to bring about the liquidation of Christianity?"
A related note: There are some today who speak of themselves as "Jews for Jesus." This is nonsense. It makes as much sense as saying "Christians for Muhammad." A Jew who accepts Jesus has cut himself off from the faith community of Jews, and that has been so for 2,000 years. Moreover, that Christians argue with the Jewish community about the legitimacy of "Jews for Jesus" is presumption of a high order. I would not presume to tell Christians who is a Christian and emphatically reject the idea that the Christian community can tell me who qualifies as a Jew.
Many Jewish thinkers have seen Jesus as they have seen Muhammad, as God's instrument to advance monotheism in the world. Franz Rosenzweig spoke of Judaism as the sun--that is the source--and Christianity as the rays of the sun--that which spreads monotheism to the world. The greatest Jewish philosopher, Maimonides, of the Middle Ages saw Islam and Christianity as the preparation for God's eventual Kingdom.