With the war in Gaza still raging, Rabbi Sharon Kleinbaum offered an unusual prayer for peace last month during a Friday night service at the large predominantly gay synagogue she leads in New York. Cautioning her flock not to “harden our hearts” against any who had suffered, she wove throughout the prayer the names of young Israeli soldiers — as well as Palestinian children — who were killed in Gaza.

The reaction was swift: A member of the board posted his resignation letter on Facebook, accusing Rabbi Kleinbaum of spreading propaganda for the militant Palestinian group Hamas, and three more congregants soon left.

From the other direction, Rabbi Ron Aigen heard criticism at his synagogue in Montreal this month after he gave a sermon asserting that in the recent battle, Israel had endeavored to live up to the highest standards of Jewish teaching on ethical and just war. He said that he received a letter from a member who had not heard the sermon, but announced that she was quitting because there was no room to express criticism of Israel in the synagogue, which is Reconstructionist and one of the most liberal in Montreal.

Forty-seven years after Israel’s victory in the 1967 Middle East war — celebrated by Jews worldwide — Israel’s occupation of Arab lands won in battle and its standoff with the Palestinians have become so divisive that many rabbis say it is impossible to have a civil conversation about Israel in their synagogues. Debate among Jews about Israel is nothing new, but some say the friction is now fire. Rabbis said in interviews that it may be too hot to touch, and many are anguishing over what to say about Israel in their sermons during the High Holy Days, which begin Wednesday evening.