After 12 hours of intensive debate stretching over two days, Israel's Cabinet last night still had not approved a draft peace treaty with Egypt. The Cabinet scheduled another round of debate for today amid indications that Israeli negotiators will bring numerous proposed revisions to Washington.

The marathon discussion of proposed changes is taking place in the face of a message from, President Carter to Prime Minister Menachem Begin on Monday night urging the Cabinet to accept the draft treaty as it is.

Begin, however, was reported to be less than pleased with the draft, although he is not prepared to reject it as long as it undergoes further revision.

The sluggish pace of the debate appeared to foreclose any chance that the Israeli delegation to the Washington peace talks could retun to the U.S. capital in time to resume negotiations before the weekend, as anticipated by U.S. officials.

The Cabinet met for seven hours without interruption yesterday and has yet to hear from six of the 19 ministers, including Begin.

As they left Begin's office at the end of the day, several Cabinet members somberly emphasized the gravity of their deliberations, some calling the decision the most difficult ever faced by the government.

Their demeanor contrasted sharply to the note of optimism struck by the Israeli delegation when it left Washington last week and by the State Department, which had said "the principal issues" were resolved as far as the Egyptian and Israeli delegations are concerned.'

Cabinet sources said the guarded remarks by the ministers portend not so much a chance of rejection of the treaty as the likelihood of numerous proposed revisions being taken to Washington by Foreign Minister Moshe Dayan and Defense Minster Ezer Weixman.

After the Cabinet session, Finance Minister Simcha Eriich said he could not remember a more serious debate since the government was formed. Justice Minister Shmuel Tamir called it "a very, very heavy responsibility on the government, and as such on every member,"

Deputy Prime Minister Yigael Yadin said, "It is a draft, and we are discussing every aspect of it. It is a peace treaty, something you don't do every day." Yadin said, however, that there was no "major problem" with the draft, and that he hoped the debate will be concluded today.

Begin told reporters at the end of the session, "It is a long debate, and no wonder, because we are dealing with the most serious problem concerning the future of our nation."

Government officials said that the issue of a written linkage between the Egyptian-Israeli bilateral pact and the question of the West Bank and Gaza Strip self-determination for Palestinians does not remain as a principal sticking point.

The wording of the linkage in the treaty's preamble, sources said, is sufficiently vague so as not to present a major obstacle by itself.

Several members of the parliament's Foreign Affairs and Defense Committee, which studied the draft after the cabinet meeting, said last night, however, that the linkage question is a major stumbling block.

Energy Minister Yitzhak Modai said he felt there were "indications of some sort of legal linkage" and that he would propose revisions.

Former prime minister Yitzhak Rabin, of the opposition Labor Party, said, "I'm concerned about two issues. I'm concerned about the way the two agreements will be linked, and when and how normalization will be established."

Yehuda Ben-Meir of the National Religious party said, "The cardinal question regarding the whole treaty is the linkage to Judea and Samaria (West Bank). I'm gravely troubled because . . . what's involved poses great danger to our position in Judea and Samaria.

"We paid a very heavy price for peace with Egypt, and the two issues cannot be connected. This is the key issue . . . It goes to the very question of Israeli's security," Ben-Meir said.

Labor Party leader Shimon Peres said, however, that he was not surprised by the draft, adding, "I believe it follows the Camp David agreements. There are some additions and changes, which really in a way don't change the character of the Camp David agreements."

Earlier yesterday, Perea complained in a Radio Israel interview that the United States was assuming a disproportionate role in the peace talks. "America is appearing more and more as the party that proposes the final drafts," he said. "Our people are a little bit taken by this fact, with the feeling that we are losing a little bit of our independence in the conduct of the negotiations."

But Peres said, he "cannot see an alternative."

Government sources said there are a number of points in other sections, including the military portion of the document, that Israel has decided are totally unacceptable.

The sources said these include an Egyptian proposal to redeploy its missiles on the West side of the Suez Canal to a point where they would gain a strategic advantage over that part of the Sinai Peninsula where Egypt would be required to reduce its forces.

They were also said to include Egypt's right to move military vessels in the Gulf of Aqaba and deploy inter-Ceptor-fighter aircraft in the Sinai where the original Camp David agreement did not envision such defenses.

Cabinet sources said, however, that they do not expect military issues to present major obstacles to a treaty signing.

News services reported the following Middle East developments:

Saudi Arabia expressed a "better understanding" of the Egyptian-Israeli peace accords after a visit by Sayed Marel, a special envoy of President Anwar Sadat, Egyptain sources said, adding however that it was "premature to say that Saudi Arabia has fully endorsed" the accords.

Sadat has invited Pope John Paul II to visit Egypt and pray on Mount Sinai after the signing of a peace treaty and the pope has "expressed a great interest," Egypt's ambassador to the Vatican, Shaffle Abdel Hamid, said in Rome.

Sadat, in a speech in Caire, relterated his commitment to self-determination for Palestinians in the Gaza Strip and the West Bank.