Actually, many Rabbis have come to believe in Jesus as the Jewish Messiah (example). Over the years I (Steven Barry Kaplan) have had many interactions with Rabbis and other leaders from the Jewish community.
Here are but a few of them:
I visited an Orthodox Synagogue in the Toco Hills area of Atlanta. As I was leaving, the Rabbi stopped me to talk. He said someone in his congregation said that I have a tendency towards Jesus? I said I am Jewish believer in Jesus. He said that I would not be allowed at his synagogue. I told him I had been thrown out of better places then his synagogue, and we both laughed. I asked him why he doesn't believe in Jesus? He told me because the Talmud negates Jesus as Messiah. I asked why he follows the Talmud rather then the Bible? He said because his father did. I asked why, and he said because his father did. I asked why, and he said because his father did. I said, what if they were wrong? The rabbi just threw his arms up to say, who knows?
While meeting with a Traditional Rabbi in Sandy Springs, Georgia, I challenged him to read Isaiah 9:6.
6 For to us a child is born,
to us a son is given,
and the government will be on his shoulders.
And he will be called
Wonderful Counselor, Mighty God,
Everlasting Father, Prince of Peace.
The Rabbi started sweating, became very nervous and started rubbing his finger between his neck and shirt collar. Next, the rabbi did something very smart, he looked the scripture up in Hebrew. He kind of smiled at me and nodded his head to say I might have something there. Sadly, a few years later the rabbi passed away in his early forties.
After many many months of Internet exchange with an Orthodox anti-missionary in Atlanta, Georgia, I asked who was being talked about in Isaiah 9:7
7 Of the increase of his government and peace
there will be no end.
He will reign on David's throne
and over his kingdom,
establishing and upholding it
with justice and righteousness
from that time on and forever.
The zeal of the LORD Almighty
will accomplish this.
The anti-missionary told me it was talking about King Hezekiah. When I pointed out the fact that King Hezekiah didn't establish King David's throne from that time and forever, he stopped e-mailing me?
I met with an Orthodox anti-missionary in Johannesburg, South Africa. I listened to what he had to say for well over an hour. After he was finished speaking, I asked a simple question. How do Gentiles go to heaven (if Orthodox Judaism is the only way to God, then billions of people who are not Orthodox Jews will have a problem)? He replied by admitting that he really struggles with that question.
I spoke with Rabbi Shmuley Boteach right after he debated Dr. Michael Brown in Montreal, Canada. Shmuley asked me how Jesus could be the Messiah since He didn't fulfill all the Messianic Prophecies. I told Shmuley Jesus fulfilled all the Messianic prophecies pertaining to His First Coming!
I attended an all night Shavout learning at a Reform temple in Dunwoody, Georgia. There was a class "How reform should we be?" People asked questions about keeping Torah and temple sacrifices without a temple. People took turns explaining what they thought it should be. I explained Jesus had become the sacrifice for sin and His death and resurrection instituted the new law as prophesied in the Old Testament. The rabbi said someone felt as though I spiritually raped her, and I must leave? The rabbi walked me to the door and I quoted Isaiah 53:6 "All we like sheep have gone astray, each has turned to his own way and the Lord has laid upon Him the iniquity of us all." The rabbi said he was familiar with that scripture and thanked me for leaving peacefully.
I had visited an Orthodox Synagogue in Dunwoody, Georgia for a singles Bible study. The Rabbi leading the study told me I had to leave, then changed his mind and invited me to debate him in front of his class. One of the major debate points was why do we need a new covenant? I told them the scripture says there will be a new covenant in Jeremiah 31:31.
31 "The time is coming," declares the LORD,
"when I will make a new covenant
with the house of Israel
and with the house of Judah.
32 It will not be like the covenant
I made with their forefathers
when I took them by the hand
to lead them out of Egypt,
because they broke my covenant,
though I was a husband to them,
declares the LORD.
33 "This is the covenant I will make with the house of Israel
after that time," declares the LORD.
"I will put my law in their minds
and write it on their hearts.
I will be their God,
and they will be my people.
34 No longer will a man teach his neighbor,
or a man his brother, saying, 'Know the LORD,'
because they will all know me,
from the least of them to the greatest,"
declares the LORD.
"For I will forgive their wickedness
and will remember their sins no more."
They said this couldn't of happened yet because verse 34 says they will all know me, and I said they all will know God in the new millennium and that the scripture is partially fulfilled at this time. The class ended and some went to the prayer meeting. They need 10 Jewish men (a minyan) in order to pray certain prayers. As fate would have it, I was the tenth man there and a debate broke out as to whether I was Jewish? The Senior Rabbi was there and said according to Halukkah (Jewish law) if someone is born of a Jewish mother, then they are Jewish. They let me stay.
I was on vacation in Athens, Greece, and I had planned to visit the local Orthodox Synagogue for a service. The airline had lost my luggage, and I was wearing a "Jesus Loves You" t-shirt. I was welcomed into the synagogue, but after a few minutes, the leader of the synagogue and some others attempted to throw me out. When it was determined I was Jewish, they allowed me to stay because they needed me for the minyan!
While distributing Gospel tracts in Delhi, India, an Orthodox Rabbi invited me to his synagogue. He asked me to repeat some Hebrew prayers. He filmed me with a camera and tried to get me to say I renounce my belief in Jesus, but I knew enough Hebrew to know what he was doing. They had me watch a video about a Jewish believer in Jesus trying to share Jesus with Rabbi Schneerson. After the believer walked away, Rabbi Schneerson said the man was ill. The Rabbi proceeded to call me ill. I told him that was Lashon Hara (Orthodox Jews are not supposed to talk bad about anyone) and he immediately stopped!
*Resource: "What the Rabbis Know About The Messiah"— Rachmiel Frydland