The seventh year of his presidency has not been a good one for Anwar Sadat or for Egypt.

On the anniversary of his accession to power at the death of Gamal Abdel Naser, Sadat presides over an impoverished, disease-ridden nation beset by political turmoil and religious strife.

Despite grand promises, he has delivered neither prosperity at home nor peace abroad to his 39 million people. His abrupt change from the inept socialism of the Nasser era to a halfhearted capitalism has done little to alleviate the poverty or ignorance of the masses, whose numbers continue to grow by a million persons a year.

Sadat's rupture with the Soviet Union has cut off his military supplies and broken the country's well-established trading patterns but has not brought the Eastern-sponsored Middle East peace on which he has been counting.

Today, in a major speech, Sadat intensified the rupture, making clear that he plans to postpone repayment of $4 billion that Egypt owes the Soviet Union for military equipment purchased in the 1950s and 60s. "I am asking the Soviet Union for a 10-year grace during which we repay nothing," he said, indicating that no money would be paid even if Moscow [TEXT OMITTED FROM SOURCE]

The Euphoria that followed the successful crossing of the Suez Canal in the 1973 war has given way to restive grumbling in a year when the armed forces have been used to put down food price riots in the cities and to administer spanking to Maummar Qadaffi's Libya.

The consumer and political ineptitude of Sadat's government, headed by a former police officer, is a constant source of worry to Sadat's supporters, Egyptian and foreign. They fear that if the situation deteriorates further he might be ousted by an extremist of the left or the right.

Yet, in the view of Egyptian intellectuals, foreign diplomats, government officials, journalists and other observers here, there appears to be no immediate danger that the government will fall. Circumstances that would bring down any government in Western Europe, they argue, mean little ina country where the president can suppress opposition with a stroke of his pen.

None of the dissident elements taking advantage of Sadat's political liberalization to oppose him has the strength to bring him down, these observers agree.

Only the army could do that, they say, and Egypt's armed forces have one of the best records in the Third World of keeping hands off government. Under the command of the rigidly apolitical Gen. Mohammed Abdel Ghani Gamassi, a Sadat loyalist, the army has so far followed orders and stayed out of politics.

Sadat has not yet given the armed forces reason to withdraw their support, informed observers say. The question is whether the failure to achieve peace, the flickering hopes for economic prosperity and the mushrooming, overt political opposition throughout the country might induce the military to act.

"The longer the situation goes on this way without any solution, the longer Sadat's American connection fails to produce a peace settlement, the greater the chance that something will happen," said Boutros Boutros-Ghali, head of the political science faculty at Cairo University.

"All these dissident elements, the Moslem Brotherhood, the leftists, could create an atmosphere in which the army would feel obliged to step in," he said.

"It's been two years since Sadat has had a policy success," said a concerned diplomat from a friendly country referring to the Sinai peace accord that involved a pullback of Israeli troops from the Suez Canal and return of captured oil fields to Egypt.

"He needs something or the situation will continue to deteriorate. When you have the appearance of a political vacuum, you get people moving to protect their own interests first and you risk chaos."

One possibility feared by political activists, students and intellectuals here is that the armed forces might act not in opposition to Sadat but in concert with him, restoring order by the imposition of military rule, as happened in the Philippines - ending the country's "democratic experiment," Sadat has repeatedly pledged that this will not happen.

He renewed that pledge in his speech today. As he has before, he acknowledged the difficulties facing the country and errors of the past. He promised better times if the people work hard and end their divisions. He said Egypt had passed the bottleneck" from economic stagnation toward progress that would give Egypt "breathing room" by 1980.

Many Egyptians argue that in the Egyptian context, the situation is not as bad as it seems to Western eyes. Corruption, poverty, disease, religious tensions and political extremism have existed in Egypt for centuries, they argue, and are no more likely to bring upheaval now then they did in the past.

Sadat, however, does often seem like one of those besieged swordsmen in the costume epics - no sooner does he skewer one foe than three others appear behind him, and by the time he finishes them off, the first is back on his feet.

In January, under pressure from the International Monetary Fund and other lenders concerned about Egypt's mammoth balance of payments deficit, the government slashed subsidies that held down the prices of basic commodities. After two days of bloody riots, the subsidies were restored.

Yet, the problem will not go away. An IMF team is due here next month and it is expected to demand an end to the subsidies as a condition for the granting of standby credits that Egypt needs to pay its existing debts. The government is looking for ways to make the inevitable price increases more palatable to the citizenry.

Today he said that the subsidy system would be reorganized so that the aid would reach only "those who really need it." But he also promised that "subsidies for bread and basic commodities will never be touched," a balancing act that the government will find difficult to bring off.

Sadat blamed the Communists for the January riots, which most observers believe attributed far more power to the Communits than they really have. As an antidote the government began quickly encouraging the activities of Moslem conservatives and fundamentalists.

In quick succession, a fanatic bank of Moslem extremists kidnapped and murdered a former religious affairs minister and launched an antigoverment terrorist campaign in the name of Islam; fundamentalist legislators in the People's Assembly sought enactment of an Islamic code, frightening the country's 2.5 million Christians, and the outlawed Moslem Brotherhood reemerged in public with a prayer rally in a downtown square.

The attempt to rewrite the country's laws to conform with Islamic code, as in Saudi Arabia, was finally cut off by the prime minister, but only after it led to violent clashes between Moslems and Christians, mostly in upper Egypt. At least five church burnings and one death were reported. Last week Sadat arranged for promininet press coverage of meetings he held with leaders of both faiths in an effort to halt the religious feuding.

In an attack that some saw as aimed at the Soviet Union, Sadat said today that the religious conflicts were the product of a conspiracy hatched in some dark corner and were "allien to our nation, shunned by people who know their national responsibility." He warned that "those who want ot fish in troubled waters are the enemies of freedom" and said he would have no mercy on anyone trying to spread chaos."

Behind all these events are the continuing rumors about personal corruption by the president, his family and his political friends. It has reached the point where one Cabinet minister is openly described at diplomatic receptions as the prime minister's "bagman."

Sadat and his wife, Jehan, certainly live very well in their many houses, but then the upper classes in general are prospering under Sadat's economic "open door" policy. After years of circumspection under Nasser, they are again flaunting their fancy cars and European clothes and expensive applicances in full view of themasses scraping by on a diet of beans and bread.

"It is a dangerous thing, in a country like this, for any leader to cast his lot with the bourgeoisie," a sophisticated political analyst said. "But who is going to push him out? The government is weak, but would another one by any better? Unless there were someone who could offer immediate solutions to the question of the Sinai and the economy, things are likely to go along as they are for a few more years."