I have reservations about the Trinity, but so did many early Christians, and the concept is lacking in the synoptic gospels. When Jews adorn Torah scrolls with silver crowns, I’m not in a position to criticize portraits of God in Christian cathedrals.

In the synoptic gospels, Jesus hardly said anything contrary to Judaism. His Sermon on the Mount is a carbon-copy of Jewish prayers and blessings. John’s Apocalypse is widely believed by scholars to be an apocryphal Jewish work. Every saying in between those two poles has parallels in the Torah and rabbinical literature.

Resurrection is not unique to Jesus. The Jewish prophet Elisha resurrected a woman. Jesus’ miracle of feeding multitudes with a few loaves of bread is also similar to Elisha’s.

In the best Kahanist traditions, Jesus declared that he has come only to Jews. He was loathe to heal a Samaritan, comparing her to a dog. Samaritans are Jewish sectarians, almost Jews, so imagine Jesus’ attitude toward Gentiles.

Jesus adhered to Jewish law. He announced, “Until heaven and earth pass away, not the smallest letter or stroke of a letter will pass from the Law.” “So whoever sets aside the least of these commandments and teaches others to do the same will be called least in the kingdom of heaven. But whoever does them and teaches them will be called great in the kingdom of heaven.” “If you want to get into the eternal life, you must keep the commandments.”

Jesus’ opinion of the rabbinical Judaism was very high: “Do everything as they tell you but not as they do, because they don’t practice what they teach.” He conceded that pharisaic rabbis held the unique key to the kingdom of heaven. He spoke in parables, a standard device of rabbinical exegesis.
Jesus accused rabbis of hypocrisy, but generally had no qualms about their teaching. He accepted the legitimacy of extra-Biblical fasts, and only argued that his students were excused from fasting temporarily, while with him. There were minute arguments, whether the oath by altar or the offering is more important, or whether it is permissible to heal on the Sabbath. Jesus was liberal by ancient standards, as he permitted his disciples to glean on Sabbath to satisfy their immediate hunger. But by now most Orthodox rabbis would concur with his interpretation. Reformist Jews are far less observant than Jesus was, and he was definitely less idolatrous than most Orthodox rabbis today. Indeed, he tried to stem the pharisaic idolatry of rites.

Jesus accused rabbis of making their tzitzit too long and tfillin too big without denying the need for either, even though other Jews besides Pharisees and Essenes didn’t wear tfillin. Indeed, Song of Songs asks the beloved to “Set me as a seal upon your heart, as a seal upon your arm,” and thus suggests wide acceptance of the tfillin commandment as a metaphor.

Jesus accepted the rabbinical expansive Oral Law when he explicitly sided with Pharisees that even precious spices such as mint and cummin should be tithed rather than basic foodstuffs only as the Torah prescribes.

Jesus questionably envisaged Judaism as a stateless religion in his order to “Give to Caesar what is his, and give what is God’s to God.” But so did the exilic rabbis in their “Law of the land is a law.”

In the synoptic gospels, Jesus never claimed any special affinity with God. Moreover, he called all Jews, not just himself, “children of God,” and God their father. Nor would it be exceptional for Jews to praise someone as a son of God; thus was called Hanina ben Dosa.

The messiah designation is theologically mundane. Rabbis declared bar Kochba a messiah, and so were Cyrus, Rabbi Luria, and recently the Lubavitcher Rebbe.

Faith in Jesus also has precedent. God stated that Jews should believe in Moses (Exodus 19:9).
Apostles received the holy spirit and started prophesying just as the seventy Jewish elders in Moses’ congregation had (Numbers 11:25). It doesn’t matter for our purpose whether the apostles’ story is true or false: it falls within Jewish law.

Jesus’ birth story cannot shock a minimally educated Jew. Samson was conceived in an equally miraculous way, and probably like Jesus, he was Nazirite. The killing of innocents at the time of Jesus’ birth is akin to the Moses’ birth account. The Magi and the star (in Beth Lehem) recall Abraham.
Why, then, oppose messianics in Israel? The mere belief in someone’s messiahship doesn’t make a Jew an apostate. At any rate, messianics are more religious than a typical reform Jew.

I have very little against Christianity: it is just an unfortunate fact that for the past fifteen centuries it has formed an ideology for repressing and killing my fellow Jews.