The conference of 38 Moslem leaders that adjourned here last night passed a resolution calling on the U.N. General Assembly to reject the credentials of the Israeli delegation and "freeze" its membership in the world body.

The resolution says Israel has violated international law by declaring Jerusalem its capital and by failing to implement numerous U.N. resolutions.

Conference sources said the Islamic Conference Organization would probably seek the take this action in the fall when the General Assembly reconvenes. Responsibility for coordination of Strategy has been given to its Jerusalem committee, headed by King Hassan II of Morocco.

The conference also called on its members to end diplomatic recognition of Israel if they have not already done so and to sever economic ties.

Conference sources said the main country affected would be Turkey, which has just reduced the level of its diplomatic representation in Tel Aviv to a second secretary and closed its consulate in Jersualem. Turkey had about $40 million in trade with Israel last year.

The Islamic Conference, in its main Mecca Declaration, condemned what it described as increasing rivalry of the superpowers in the Middle East and Persian Gulf and their efforts to obtain military facilities there.

The statement says the nations of the region have "exclusive responsibility" for "peace and stability" there, including protection of the sea lanes.

Finally, Saudi Arabia announced a new $1 billion contribution to banks aiding the economic development of poor Islamic Third World Nations, with the Islamic Bank receiving a large share. Kuwait, the United Arab Emirates and Qatar pledged another $1.3 billion for the same purpose.