For the thousands of Antiochian Orthodox Christians gathered in Washington this week for their annual continentwide convention, the center of interest is less in the sessions scheduled at the Sheraton Park Hotel than in the black-robed figure who presides ove them.

He is Patriarch Elias IV of the ancient Sec of Antioch, who is winding up an unprecedented three-month visit to North America by attending the week-long convention here of his North American Church.

Patriarch Elias, who holds the same position for his follwers that Pope Paul VI does for Roman Catholics, is the first of 164 Antiochian patriarchs since the time of Christ to visit this country.

"His beatitude is very impressed by the vitality of the Antiochian Church in this country and particularly by the faithfulness of the new generation and their concern for the life of the church," the patriarch's spokesman-interpreter told a news conference this week.

Since his arrival in this country in May, the patriarch has traveled from coast to coast and attended six regional parish life conferences, said the spokesman, Metropolitan Philip Saliba of New York, who heads the North American Archdiocese of the church.

The church, once known as the Syrian Orthodox Church, has 50,000 "dues-paying" members in North America, the metropolitan said, and another 300,000 who have a more casual relationship with the church.

Earlier this month Patriarch Elias met with President Carter when, he told reporters, he "urged the President to use his influence to bring peace in the Middle East."

The Lebanese-born churchman said he believes that "without a solution to the (Palestinian) homeland problems, it is difficult to see how there can be a solution" to the Middle East conflict.

He blamed that conflict on "Zionist elements who migrated to the area after the Balfour Declaration and the tragic events of World War II."

He cited the question of restoration of a homeland for Palestinians as the first prerequistie for peace and the "withdrawal of (Israeli) troops from occupied Arab lands" in what is now Israel, as the second.

The patriarch's ancient headquarters are in Antioch, Syria. The Patriarchate of Antioch is one of the five ancient sees of Christendom. The others are Alexandria, Constantinople, Jerusalem and Rome. There are an estimated 6 million to 8 million Orthodox Christians worldwide.

The patriarch terms his followers in the Antiochian Orthodox Church "Christian Arabs." He has actively made common cause with Muslim Arabs, with whom, the patriarch said, "we are in solidarity."

Wednesday night, the patriarch and the American clergy of the church were the guests of honor at a dinner hosted by ambassadors of the Arab states.

In his news conference, the patriarch challenged the view of many Jews that God's promise to give Israel to the Jews, as recorded in the Old Testament, justifies the modern Jewish state.

Speaking through his interpreter, he said, "As far as we Christians are concerned, we are the new Israel. The coming to the Messiah has fulfilled all the Old Testament prophesies."

He added: "All the prophesies of the Old Testament were fulfilled by the coming to the Messiah . . . After the destruction of the temple (in Jerusalem in approximately 70 A.D.) the Jews were dispersed. Those who remained lived in peace with the Arabs and the Christians" until modern times when, he said "outsiders" came in.

A leaflet distributed by the church quoted thepatriarch as saying that" as Christian Arabs, we believe that the loss to Jerusalem affects the Arab cause in general. We shall not spare any effort to insure that Jerusalem remains an Arab city, open to all believers and to the entire world . . . The Palestinian ples is for a Jerusalem returned to its own people."

The churchman also asserted that "the exiled and dispersed Palestinians are the symbol of all human suffering."

The Patriarch said he is striving both in this country and throughout the Orthodox world for pan-Orthodox unity, which, he said is "inevitable."

Through the interpreter he said. "Inspite of ethnic difference we have unity of faith. We have the same dogma, the same doctrine, the same traditions."

He said the question of unity would be a major topic in the forthcoming pan-Orthodox synod, which is now in the preparatory stages."

The Patriarch said that during his interview with President Carter he was "inspired by the President as a man of faith." He reported that the President asked three times, during the conversation, for the Orthodox leader's prayers.

The patriarch pledged that he would light a candle for the President at the oldest shrine in Syria, near Damascus, when he returns home next month.

Convention delegates adopted, unanimously, four resolutions dealing with the Middle East. U.S. leaders were urged to press for an end to "illegal settlements on occupied territory in Israel."

A resolution on human rights in Israel demanded that the United States withhold economic and military aid from Israel, charging that Israel violates human rights of Arabs within its borders.

Another urged American churches to conduct Islamic-Christian dialogues "in the interest of world peace."

A fourth, calling the Arab-Israeli conflict "the most poorly reported news story in the history of American journalism," calls on the communication media to "stop being part of the insidious campaign to misrepresent the Arab world" and to "start publishing the truth."