Bob Mendelsohn has been wearing 'Jews for Jesus' slogan T-shirts since bell-bottoms were in fashion — the first time around.

As a Messianic Jew, he views Jesus as the messiah; not just for Christians, but for all people, including Jews.

It's a controversial belief, and one that gained international attention a fortnight ago when US Vice-President Mike Pence invited a Messianic Jewish leader onstage during a rally for the Pittsburgh synagogue shooting victims.

The Jewish Democratic Council of America condemned this decision, stating: "So-called Messianic Jews are not a part of the Jewish community, and espouse views considered deeply offensive."

Reasons for the rift

Jesus was Jewish, but it's Christians — not Jews — who view him as the messiah.

Hebrew scholars and philosophers argue Jesus is a 'false messiah' because he didn't fulfil messianic prophecies, such as building the Third Temple in Israel and ushering in an era of peace.

Messianic Judaism, which gained prominence in the 1960s and '70s, promoted a new narrative — one that Mr Mendelsohn, national director of Jews for Jesus Australia, wholeheartedly supports.

"The Jews for Jesus organisation began in 1973 with a handful of mostly ex-hippies in San Francisco who had come one-by-one to faith in Yeshua (Jesus), and who wanted to not only identify with him but with our Jewish culture," he explains.

Messianic Jews, like Mr Mendelsohn, refer to Jesus by his Hebrew name Yeshua. ( Supplied: Bob Mendelsohn )

"We didn't give up being Jewish any more than an Australian who moved to Paris would give up Vegemite — we're still who we are."

RN presenter and religious scholar Dr Rachael Kohn completed her doctorate on Messianic Judaism.

She says the religious tradition is somewhat of a "rebranding" of the 19th century Hebrew-Christian movement.

"It consisted of Jewish converts to Christianity, who were never made comfortable in churches due to anti-Semitism and founded their own congregations," she says of the earlier tradition.

But unlike Hebrew-Christianity, Messianic Judaism endorses Jewish rituals.

"[These include] observing the Sabbath on Friday night to Saturday night; celebrating the Passover, as Jesus had done; and other calendar and ritual observances, such as circumcision, praying with a talit or prayer shawl, and even keeping kosher," Dr Kohn points out.

Mr Mendelsohn says Messianic Judaism sprang up at the same time as the Christian "Jesus movement" in the '60s and '70s. ( Supplied: Bob Mendelsohn )

'Hebrew roots'

It's not just Jews who are part of the contemporary Messianic movement.

Les Aren Gosling, a lecturer for the International Messianic Community of Faith, says "gentiles" — non-Jewish people — are also active participants.

"In all the Messianic congregations around the world there are perhaps more gentiles than there are Jews," he says.

"When people say, 'Oh you're a messianic believer?' You've got to qualify it and say, 'Well yes, I'm a Messianic gentile or a Messianic Jew'."

According to Dr Kohn, the presence of gentiles in Messianic Jewish communities isn't as strange as it sounds.

"Gentiles make up a significant proportion of the membership of Messianic Judaism for two basic reasons: the first and most common is that they have married a Jewish convert," she explains.

"The second and most interesting reason is that the adoption of Jewish practices of the kind Jesus might have engaged in draws the believer nearer to him, and away from the church tradition that was largely a product of the Roman emperor Constantine."

Jews for Jesus in Bondi Junction is the only store in Australia offering Messianic Jewish items. ( ABC RN: Siobhan Hegarty )

Shannon Eades fits into the latter category.

He lives in Port Macquarie on the New South Wales central coast, and is part of a community called the Ancient Foundation Bible Fellowship.

"We're not actually Jews, but we run along the same vein and believe in all of the things they believe in," Mr Eades explains.

"Another term is Hebrew roots — gentiles who are going back to the Hebrew roots of their faith."

Mr Eades came across the Messianic movement six years ago, after becoming disillusioned with the Christian church he was attending.

He says most members of the fellowship — which is entirely gentile-based — had similar experiences.

"They've come from various church backgrounds: from Pentecostal churches to the more traditional Catholic, Uniting, Anglican church backgrounds," he says.

"It's just all variety of people that have sensed that there's more to what they've been experiencing in their religious walk."

But his practice goes deeper than beliefs. He, and fellow community members, mark the Sabbath each Saturday and, where possible, keep a Kosher diet.

"We don't eat any fish that don't have fins and scales; we don't eat any pork products; and we don't eat any shellfish like prawns or lobster," Mr Eades says.

Messianic Jews view the New Testament as a complement to the Hebrew Bible, the Tanakh. ( ABC RN: Siobhan Hegarty )

Alienation and threats

The fusing of Christian and Jewish beliefs is provocative for most Jews and Christians who have defined themselves by separate traditions for nearly two millennia.

According to Dr Kohn, it's the missionary aspect of the Messianic movement that causes the greatest concern to the Jewish community.

"After surviving the Holocaust, for Jews to be targeted by a proselytising group is deeply threatening," she says.

"The fact that we're so small, we're 16 million people worldwide, means that survival is key to our future."

Mr Mendelsohn says Jews for Jesus has faced hostility from some "extremist" parts of society.

"Most Australians are very happy to allow someone who has a different believe to have their belief," he says.

"But we've experienced some hostility. Our windows have been smashed at our bookshop in Bondi Junction; threats; paint thrown on our vehicles.

"It was certainly not by the mainstream of Jewish or Christian thought."

For Mr Gosling, who lives on the Gold Coast, alienation doesn't just come from extremists.

"If I go to a Sunday [Christian] service, just out of curiosity or whatever, I don't wear my yarmulke, I don't wear a skullcap, I don't wear a kippah," he says.

"It just brings unwanted attention to me, certainly in a hostile way.

"I once had a pastor and his wife ask me, very politely, to leave. You don't get the so-called Christian charity if you go in there — they see you as a threat."

The store's exterior was vandalised in 2005. ( Supplied: Bob Mendelsohn )

Despite that confusion — and, at times, discrimination — associated with Messianic Judaism, Mr Gosling says his faith is entirely valid.

"You can be a Buddhist, you can be a Hindu, you can be a gangster like Bugsy Siegel and Meyer Lansky ... and still be seen as Jewish and acknowledged as such," he points out.

"But if you believe in Yeshua as the messiah you are unceremoniously rejected and denounced and no longer considered a legitimate Jew.

"It's entirely fallacious."