After having spent more than 20 years in Messianic Judaism, I understand the Jewish people believe that if a Jew comes to Jesus, then he/she is no longer Jewish; but Messianic Jews would disagree with this and would say that Y’shua is the Messiah, and what could be more Jewish than to believe on the one who was promised and the one who was sent.
Messianic Jews have come to believe based on Y’shua’s fulfillment of scripture. Many have had no contact with “missionaries” whatsoever, but came to believe by a revelation through reading their own scripture.
Verses such as:
– Born in Bethlehem (Micah 5:2/Matthew 2:1-6)
– Rejected by his own people (Isaiah 53:1,3; Psalm 118:22)
– Tried and condemned for the transgression of the people (Isaiah 53:7&8)
– Your king comes to you humble and riding on a donkey (Zechariah 9:9/Matthew 21:5)
– This is just a very, very small sample. (And of course there are arguments against this interpretation from main-stream Judaism.)
Sometime before Jesus came, the Rabbis classified miracles into two different categories: miracles that anyone could perform and miracles that only the Messiah could perform. These Messianic Miracles were based on Isaiah 35:5-6. It is recorded that Jesus performed all these miracles: He healed Jews with leprosy, he healed those born blind from birth, he cast out dumb spirits, and he raised the dead after 3 days (referring to Lazarus) (see
The Four Messianic Miracles) There were certain miracles which he performed which he told the one who was healed, “Go and show yourself to the Priest.” These were the miracles that only the Messiah could preform. Jesus was trying to tell them that He was the One.
If a Jewish person comes to Y’shua Jesus, then he/she would join the ranks with hundreds of thousands of Jewish people world-wide from all walks of life–Rabbis, Orthodox, Reform, Conservative, Hassidic, who have come to believe also. They would say that they have not defected from Judaism, but have come to its fulfillment.