It is one of the many paradoxes of the Islamic Republic of Iran that this most virulent anti-Israeli country supports by far the largest Jewish population of any Muslim country.

While Jewish communities in Syria, Iraq, Yemen, Egypt, Morocco and Algeria have all but vanished, Iran is home to 25,000 - some here say 35,000 - Jews. The Jewish population is less than half the number that lived here before the Islamic revolution of 1979. But the Jews have tried to compensate for their diminishing numbers by adopting a new religious fervor.

But Khomeini met with the Jewish community upon his return from exile in Paris and issued a ''fatwa'' decreeing that the Jews were to be protected. Similar edicts also protect Iran's tiny Christian minority.

Still, Jewish leaders say their community has far stronger roots in Iran than other Middle East Jewish communities, which were virtually eradicated by massive immigration to Israel in the 1940s and 1950s. Esther, the biblical Jewish queen who saved her people from persecution in the fifth century B.C., is reputed to be buried in Hamadan, in western Iran. The grave of the Old Testament prophet Daniel lies in southwestern Iran.

''We are different from the Jews of the diaspora. You see the name 'Persia' in the Old Testament almost as often as the name 'Israel.' The Iranian Jews are very much part of Iran,'' said Gad Naim, 60, who runs the old-age home in Tehran. Iranian Jews trace their history to the reign of Persia's King Cyrus. As the Bible tells it, Cyrus conquered Babylonia in 539 B.C., liberated the Jews from captivity, and raised funds for the rebuilding of their destroyed temple in Jerusalem. The return of the Jews to Jerusalem at that time was accompanied by a large migration to the lands that were then Persia, and now Iran.

Although he is virulently anti-Israel in his public comments, Khatami was considered sympathetic to the Jews during his term as Iran's minister of culture and Islamic guidance. He paid a campaign visit to a social club for Jewish women in Tehran. ''We expect more freedom, an easier life, not just for Jews, for everybody,'' said Farangis Hassidim, an administrator of Tehran's Jewish hospital.

Not everyone in the Jewish community favors liberalization of Iranian society. Arizel Levihim, 20, a prospective Hebrew teacher, said Judaism has fared better within the confines of Iran's strictly religious society. ''I believe it is good for women to keep their head covered. I think it is good to restrict relations between boys and girls,'' Levihim said. ''I agree with the ideals of the Islamic republic. These are Jewish values too."