For the first time since Israel was created 30 years ago, Israeli Moselems are being permitted to participate in the hajj - the pilgrimage to Mecca - that is one of the requirements of Islam.

Thirsty busloads of about 1,500 Israeli Arabs crossed the Allenby Bridge over the Jordan River yesterday on their way to Amman, Jordan, and ultimately to the holy city in Saudi Arabia. It is the first time the Arab states have allowed Moslems from Israel to travel through their countries on the hajj.

For the Israeli Arabs, it was the fulfillment of a dream and the end of three decades of frustration at being unable to observe this Islamic commandment.

Most of the passengers were elderly, reflecting in part a decline of religious observance among the younger generation, but indicating also that to many of the Moslems the trip was a fleeting opportunity to visit the holy city at least once in their lifetimes, in accordance with the spiritual commandment.

Until now, Jordan and Saudi Arabia have refused Israeli citizens permission to travel to Mecca, saying they have bound by decisions of the Arab League. There are approximately 550,000 Arabs with Israeli citizenship who are - or are descended from - Palestinians who chose to remain here after the war of independence in 1948.

Last year, a symbolic delegation of 31 Israeli Arab notables was permitted to travel to Amman to extend condolences to King Hussein following the death of Queen Alia. At that time, they handed the Saudi charge d'affaires a letter to King Khalid asking the Saudi monarch for permission to make the pilgrimage to Mecca.

That step coincided with efforts by Sen. Richard Stone (D-Fla.) to allow the Israeli Arabs to join their fellow Moslems in Mecca. Stone gained an audience with Khalid and, following strict Saudi protocol, asked if he could petition the king for a "religious favor."

Later, Stone also persuaded the Jordanian government to appeal to Khalid.

Israeli Prime Minister Menachem Begin's adviser on Arab affairs, Moshe Sharon, said the pilgrims entered Jordan on a special permit issued by the Israeli Interior Ministry, and that they were then issued Jordanian visas for the remainder of the trip.

As the Israeli buses pulled up to the border bridge yesterday for the transfer to Jordanian vehicles, they noticed that Jordanian travel agents - apparently assuming the Israeli Moslems were all wealthy - had lined up air-conditioned luxury tour buses that previously had been used for the Tehran-to-Istanbul tourist circuit. Each had an Iranian driver.

Iran is the only nation in the Middle East with which Israelimaintains commercial relations.

In a departure from border routine, the Israeli Army permitted the Jordanian-chartered buses to drive all the way to the Israeli side of the bridge to pick up the Moslems, who had spilled out of their Israeli buses and were lined up along the road.

As Arab tea vendors and money changers from nearby Jericho plied their trades among the colorfully dressed crowd, the pilgrims began singing the traditional high-pitched hajj pilgrimage song. One pilgrim, Mohammed Gara, said, "All Arabs of the land of Israel are very happy now. This night we will not be sleeping."

Sharon boarded the first bus to cross the bridge and made a short speech in Arabic, which the Moslems warmly applauded.