Once every 33 years, the religious holidays coincide so that one of the biggest feast days of the year for Muslims falls on the biggest fast day of the year for Jews.

This year, Yom Kippur will coincide with the Muslim holiday of Eid al-Adha, the second most important holiday in the Muslim calendar, and the faiths radically opposed ways of marking their holidays have some worried that interfaith tensions may rise even higher than in past years.

Eid al-Adha means “The Feast of the Sacrifice” and commemorates Abraham’s willingness to sacrifice his son. The festival is often marked with the slaughter of a goat or sheep, and families travel to get together in a celebratory mood.

Yom Kippur, on the other hand, the Jewish day of judgement, is marked by fasting and prayer. Secular Jews mark the day by refraining from driving cars, in what has become an inseparable cultural aspect to the holy day.

The phenomenon of a shared date happens once every 33 years – in 1948, in 1981, and in 2014. Due to the quirks of the Jewish leap year and the fact that the faiths use different lunar calendars, it will also happen again next year.

Tensions are already high between Arabs and Jews after the war in Gaza this summer and near-constant rioting in East Jerusalem.

The confluence of the two holidays has some worried that any interaction or misunderstanding between Jews and Arabs could quickly degenerate into widespread violence as it has in years past.

Palestinian youth take cover behind a wall as they hurl stones at Israeli policemen during a protest in the neighborhood of Wadi al-Joz in East Jerusalem on September 7, 2014. (photo credit: AFP/Ahmad Gharabli)

Palestinian youth take cover behind a wall as they hurl stones at Israeli policemen during a protest in the neighborhood of Wadi al-Joz in East Jerusalem on September 7, 2014. (photo credit: AFP/Ahmad Gharabli)

Police aren’t taking any chances. National Police spokesman Micky Rosenfeld said the police will increase their presence in mixed cities, especially in Jerusalem and Acre.

The police try to limit their patrols in cars on Yom Kippur but will have more policemen patrolling the area on foot. The Old City is an area of special concern. “There are tensions, but police officers have met with leaders in different communities to coordinate the fact that holidays are falling at the same time,” Rosenfeld said.

In Acre, which saw riots on Yom Kippur in 2008 when an Arab resident drove through an observant Jewish neighbourhood blaring music from his car stereo, local Muslim official Abbas Zakur said an agreement had been reached between the two communities on the timing of celebrations. Muslims would celebrate and feast on Sunday, but from Saturday small electric cars will be provided for those wishing to go to the mosque to pray.

The electric cars would create less noise than motorized vehicles and would be less likely to upset religious Jews, Zakur explained. The old city of Acre would be closed to all traffic, he added.

In the city of Hebron, which sees daily confrontations between Jewish settlers and Palestinians — or between Palestinians and police — soldiers will be manning dozens of checkpoints.

The IDF said it would implement a general closure of the West Bank and Gaza starting at midnight Thursday night and lasting until Saturday night. Palestinians will only be allowed into Israel for humanitarian reasons or for emergencies.

Each religions’ customs for celebrating their holy day could also lead to increased tensions.

“The way that the Jews celebrate [Yom Kippur] is very internal,” explained Rabbi Michael Melchior, a former MK who is also the chairperson of Mosaica Center for Interreligious Cooperation, a group promoting religious tolerance and understanding across the Middle East. “We go inside ourselves on Yom Kippur, looking at our relationships and ourselves. As opposed to other [Jewish] festivals, we go into our homes and into our synagogues, it’s not a day of external celebrations.”

“This is the exact opposite of Eid al-Adha, which is very much an external festival,” he added. “They visit each other, they travel to visit family and friends, they have a custom of going to visit graveyards, they play music. So if you don’t know that it’s a festival, some Jews might assume that the Muslim celebration is a provocation or something, which is of course not intended in any way.”

An Egyptian butcher measures the wight of a sheep on a sidewalk Sunday , part of an unseen cluster of sheep that is offered for sale in preparation for Eid al-Adha (Photo credit: Nasser Nasser/ AP)

An Egyptian butcher measures the wight of a sheep on a sidewalk Sunday , part of an unseen cluster of sheep that is offered for sale in preparation for Eid al-Adha (Photo credit: Nasser Nasser/ AP)

Over the past seven weeks Mosaica engaged religious leaders from both sides in an intensive attempt to try to combat this lack of knowledge.

The Chief Rabbis of Israel put out a statement to encourage Jews to be respectful of their Muslim neighbors customs. The Education Ministry send a letter to all students explaining the holiday.

Neighborhood rabbis of cities with mixed Arab-Jewish populations have appealed to their congregations for calm.

On Thursday, Interior Minister Gideon Sa’ar urged all mayors and religious leaders, both Jewish and Muslim, to work toward “creating an atmosphere of mutual respect, understanding, consideration and tolerance among the people of Israel.”

The statement came as Sa’ar and President Reuven Rivlin met with Muslim religious and city leaders in the northern town of Kafr Yassif  to promote interfaith understanding as the two holidays collided.

On the Muslim side, the Ulama, the highest council of religious leaders and teachers and imams of Palestine and Israel, put out a strong statement encouraging Muslims to respect their Jewish neighbors and not provoke them unnecessarily, Melchior said.

The statement will be read in most mosques across the country on Friday and was published in all major Arabic media.

“Some wonderful things have happened in these last few weeks which have been unprecedented and even sensational,” said Melchior. “One of the Islamic scholars said to me: this is the first time since the Rambam, since Maimonides, that the leaders of Islam and the Jewish leaders have together written a very strong statement to respect each other’s holidays. This is a historic document, this hasn’t happened for 1,000 years. I think this is a very positive sign.”

A Jewish man places a note at the Western Wall, the holiest site where Jews can pray, ahead of the Jewish New Year in Jerusalem's old city, Wednesday, Sept. 24, 2014. (photo credit: AP/Sebastian Scheiner)

A Jewish man places a note at the Western Wall, the holiest site where Jews can pray, ahead of the Jewish New Year in Jerusalem’s old city, Wednesday, Sept. 24, 2014. (photo credit: AP/Sebastian Scheiner)

Melchior added that even in years that don’t immediately come on the heels of a war, or feature two major holidays on the same day, there are still a few points of friction between Jews and Arabs on Yom Kippur in mixed cities.

He said frequently on Yom Kippur he is called to Hebron Road, a major thoroughfare in Jerusalem that leads to Arab neighborhoods and Bethlehem, to try to calm down groups of Jews throwing rocks at Arab cars driving through.

“This year, especially, it’s happening on such a gloomy background,” said Melchior. “We’ve had bad riots here in Jerusalem over the past couple of months and a terrible war this summer. There’s been a lot of bloodshed and a lot of bad feelings. I would like to take this to a place of tikkun, of healing. Maybe this is a sign that we will be going to a better place.”

AFP contributed to this report