The top rabbis of the three branches of Judaism in this country -- Orthodox, Conservative and Reform -- have formally endorsed Walter F. Mondale, in a move that is believed to be unprecedented in the American Jewish community.

Rabbi Louis Bernstein, New York, president of the Orthodox Rabbinical Council of America; Rabbi Wolfe Kelman, New York, executive vice president of Conservative Judaism's Rabbinical Assembly, and Rabbi Gunther Plaut, president of the Central Conference of American Rabbis, the Reform rabbinate, have written their constituencies urging support for the Mondale-Ferraro ticket. Plaut currently lives in Toronto but maintains his citizenship in this country, where the overwhelming majority of Reform rabbis live.

In explaining how they came to their conclusions, the rabbis cited the records and the stances of the candidates on such matters as church-state separation and religious liberty, a range of social-justice issues and questions of disarmament and nuclear policy as well as the so-called Jewish issues.

Bernstein, as a New Yorker, specifically praised Geraldine Ferraro from the vantage point of "a neighboring congressional district in Queens," stating that "her qualifications are superb and her credentials impeccable."

A National Council of Churches fact-finding team of visitors to Nicaragua has found no evidence of a policy of religious persecution by the Sandinista government, a spokesman said.

The Rev. James Cogswell, an NCC official who headed the six-member delegation visiting that country, acknowledged that there is "a church-state confrontation" in Nicaragua. He attributed this to tensions within the Nicaraguan Catholic Church between the hierarchy, which he said opposes the Sandinistas, and progovernment priests.

The NCC team visited the Central American country in the wake of charges from the conservative Institute on Religion and Democracy that the government was deliberately persecuting the church.

Cogswell said that the NCC team found some incidents of harassment and violations by supporters of the Nicaraguan government. But he said such events were due to local abuses rather than any overall policy. He said there is some evidence that the Catholic hierarchy is collaborating with outside forces interested in the overthrow of the Sandinista regime.

He acknowledged that the Sandinistas "have made some serious mistakes," in dealing with religious issues, but added, "They have shown an openness to know where they have made mistakes."

On another front, the National Council of Churches' dialogue with churches in the Soviet Union suffered a setback last week when a member of the delegation of U.S. church leaders was denied a visa to participate in a planned visit there.

Only hours before the 17-member group was scheduled to leave New York last week, the group learned that the Rev. Leonid Kishkovsky, assistant to the chancellor of the Orthodox Church in America, had been denied a visa by the Soviet Union. Appeals to the Soviet embassy here were unavailing.

To protest the Soviet government's action, the NCC reduced the size of its delegation to 14 and discarded much of its agenda for formal dialogue with Soviet churches in order to press discussions with both Soviet church and government authorities on the problems raised by the visa denial.

Baltimore's Auxiliary Bishop P. Francis Murphy told worshipers at the Cathedral of Mary Our Queen the church has a responsibility to address social and moral issues in politics but should not tell church members how to vote.

Murphy also argued against voting on a single issue, such as abortion or disarmament.

"Each candidate should be measured against all the issues involved in a consistent ethic of life, and in making our choices about policies and candidates, they should be considered in light of their ability to respond to all these dimensions," he said.

People in the News: Episcopal Bishop Robert Hall of Virginia has announced that he will retire Jan. 27, 1986. His successor, Bishop Peter Lee, was elected and consecrated earlier this year and is serving as coadjutor bishop.

The Rev. Paul E. Hansen, formerly of Green Lake, Wis., is the new pastor of Burke Community Church in Springfield.