Rabbi Rafi Goodwin was taken to hospital after the assault outside Chigwell and Hainault Synagogue in Chigwell on Sunday, May 16.
Essex Police say two teenagers - between the age of 15 and 18 - stepped out in front of his car and shouted at him “in a derogatory way about his religion” at around 1.15pm.
The rabbi, who was born in Leeds and attended Leeds Grammar School, was attacked with an unknown object and his phone was stolen after he got out of the car.
“Detectives are progressing their investigation following reports of a religiously-aggravated assault in Chigwell,” said a police spokeswoman.
“The two boys – believed to be aged between 15 and 18 – are believed to have left the scene on foot.
“They have both been described as being of Asian ethnicity, one was 5ft 9ins tall and wore his hair in an Afro-style and the other was described as being 5ft 7ins tall.
“Both wore black jackets and the latter wore grey tracksuit bottoms.
“We know that this incident may be concerning for those in the local area, and we are working quickly to identify those responsible and to liaise with community leaders for any further support for those impacted.”
Jas Athwal, leader of Redbridge Council, said he was "deeply disturbed and saddened" to hear about the "unprovoked and cowardly attack”.
"Antisemitism has no place in our society and if you have any details relating to this unprovoked and cowardly attack, please contact the police, information can be provided confidentially," he said.
"We are proud of our rich diversity and active faith communities in Redbridge have a long track record of supporting each other.
"All parts of the community in Redbridge unequivocally condemn this attack and continue to work together to support each other.
"I am in regular contact with senior police officers to ensure the safety of local people. As a precautionary measure, police patrols are being increased around Synagogues across the borough.
"Redbridge Council has offered all the support we can to the police to bring the perpetrators to justice and ensure the safety of worshippers going forward."
He added: "I want to extend my deepest sympathy to Rabbi Rafi Goodwin during this difficult time and myself, the police and Redbridge Council staff stand ready to support and assist the Chigwell and Hainault Shul.”
Community Security Trust (CST), a charity set up to protect British Jews from antisemitism, has released a statement which says there has been "a sharp rise in antisemitic incidents in the UK" and they are "linked to the conflict in Israel and Gaza".
"This includes verbal abuse, threats and a very large amount of hatred in social media and online," it added.
"We have also seen numerous anti-Israel demonstrations featuring large crowds of angry protestors, a minority of whom have used antisemitic chants or placards."