What was going on when I was born?

The Milwaukee Brewers, ordered by their manager four months ago to go out and enjoy themselves, completed that assignment today by winning the American League pennant with a 4-3 victory over the California Angels. The victory, achieved on Cecil Cooper's bases-loaded, two-run single with two out in the seventh inning, catapulted the Brewers into their first World Series in their 13-year history. The Brewers, who won the Eastern Division title on the last day of the season by beating the Baltimore Orioles, also became the first team in the 14-year history of championship series play to win the three-of-fivegame series after losing the first two games. ''I had all the confidence in the world we were going to come back and win the thing,'' said Harvey Kuenn, who replaced Bob (Buck) Rodgers as the manager June 2 with the Brewers tied for fifth place and seven games out of first. It was at his first meeting with the players that Kuenn told them to go out and have fun.

A Yeshiva University professor has cracked a 2,000-year-old linguistic puzzle and discovered portions of Jewish psalms addressed to Egyptian gods in a previously untranslatable Egyptian manuscript. The scholar, Dr. Richard C. Steiner of the university's Bernard Revel Graduate School, said the discovery might provide the earliest concrete evidence that the psalms were used for worship outside of Jerusalem, as well as a rare and early example of an ancient religion borrowing another's rituals. Dr. Steiner, a linguist, also said the translation would be of immense help in understanding how Aramaic, a Semitic language with some parallels to ancient Hebrew that was the lingua franca of the ancient Near East for centuries, was spoken. He and Dr. Charles F. Nims, professor emeritus at the University of Chicago's Oriental Institute, will report on their analysis of the so-called ''mystery papyrus'' in a forthcoming issue of the Journal of the American Oriental Society.

The chief negotiators for the National Football League players and owners agreed today to seek Federal help to end the impasse that has wiped out the National Football League schedule for the last three weekends. In a secretly called meeting at the Rye Town Hilton Hotel, they agreed to ask Kay McMurray, the director of the Federal Mediation and Conciliation Service in Washington, to help them find a mediator satisfactory to both sides. The agreement to have a mediator join the negotiations was the first sign of progress in the strike, which becomes three weeks old Monday. The first indication that this meeting was unlike many of those that proceeded it was the way it ended. Standing before newsmen, smiling and joking after the four-hour session, were Jack Donlan, the executive director of the National Football League Management Council; Ed Garvey, executive director of the N.F.L. Players Association; Gene Upshaw, president of the Players Association, and Sargent Karch, a lawyer for the Management Council.

Israel announced today that its troops would not withdraw from Lebanon until the Beirut Government signed a security agreement with Israel and all Israeli prisoners in Syrian and Palestinian hands were returned. The decision came in a four-and-a-half-hour Cabinet meeting designed to set forth Israel's bargaining position in the coming negotiations for a mutual Syrian and Israeli departure from Lebanon. The talks with Syria are being held through American mediation. The Cabinet repeated its earlier demand that the Palestine Liberation Organization leave the country first, before the mutual withdrawal begins.

A buying panic erupted in the credit markets last week, bringing spectacular price gains and yield declines and leading Wall Street professionals to forecast even lower interest rates in the weeks ahead. The Federal Reserve, they say in substance, will encourage a further decline in rates because of its basic motivation to shore up the nation's faltering economy. Their forecast was strengthened Saturday when Paul A. Volcker, chairman of the Federal Reserve Board, said in a speech to the Business Council meeting in Hot Springs, Va., that the Fed would tend to ignore erratic data on the money supply in the weeks ahead. In effect, Mr. Volcker said, the Fed realizes that technical factors - especially the recycling of ''All Savers'' deposit money through the banking system - would distort money supply figures and that these figures thus should not be followed too closely in trying to influence interest rates by managing the money supply.

The Rev. Maksymilian Kolbe, the Polish priest who volunteered in Auschwitz to die in another man's stead, was proclaimed a saint of the Roman Catholic Church today. Among the 150,000 people who filled St. Peter's Square for today's canonization ceremony was a haggard, tall and gray-haired Polish peasant. At the end of the three-hour rite, Pope John Paul II, who had presided over the ceremony, descended from the altar erected on a platform in front of the doors of St. Peter's Basilica and walked over to the man. The Pope, his face marked by emotion, embraced the old man and kissed him. The 82-year-old man was Franciszek Gajowniczek, a former inmate who still has his Auschwitz Camp number, 5659, tattooed on his forearm.

An explosion ripped through a chemical plant here early this morning, injuring three workers - two of them critically - and touching off a fire that engulfed large portions of the plant. Fearing toxic fumes, authorities ordered workers removed from nearby plants and closed the upper Newark Bay and part of the Passaic River for much of the day. Officials said the threat of poison gases and of the release of toxic chemicals into Newark Bay appeared not to have materialized.

Only a few years ago, the entire population of the country's judges who were women could have met in a very small room. This weekend, a mere 25 percent of them converged on New York City, and they were more than 200 strong. The occasion was the fourth annual convention of the National Association of Women Judges, concluding today at the St. Regis-Sheraton Hotel. The judges, from as far away as Alaska and as near as Foley Square, came to share their achievements and problems and to savor their recent accomplishments, particularly the elevation of a charter member, Sandra Day O'Connor to the United States Supreme Court. Most of all, though, they came to exchange insights into the difficult and sometimes isolated lives they lead as women on the bench and to escape the arduous task of trailblazing.

''The tragic fate of so many Jews destroyed without pity in the concentration camps has already been condemned, firmly and irrevocably, by the conscience of humanity.

This looks like any number of old Northeastern factory towns. The only employer of any consequence is represented by a sprawling brick edifice of little architectural note beyond its sheer bulk, but the employer in this case is a hotel, the Homestead. Unlike most old factories, everything works at the Homestead, from the four-sided clock just under the thumb-like dome to the doors of the generous veranda, which are opened and closed, not by some electronic wizardry, but by green-uniformed floor men who align themselves almost invisibly with the hinges. Countless Amenities The Homestead offers countless amenities for the protection and enjoyment of those who can pay its princely prices, enough even to satisfy men who travel by corporate jet and bring home, many of them, a million dollars a year. One hundred of those men, current and retired chief executives of many of the country's biggest companies, have just spent three days here, each day threatened by rain that they had the luck or authority to defer until most had departed. Twice a year these men, members of the Business Council, make a pilgrimage here with their wives to ponder the world beyond them in private meetings with high Government officials.

The chairmen of many of the country's biggest corporations are saying that the Federal Government's deficit has become so large that the Reagan Administration should consider cuts in military spending, along with cuts in spending on Social Security. Some of their companies count on the Pentagon for much of their business, and the military equipment industry is one that has thrived in the recession. But the executives fear that the Federal deficit, which many economists expect to reach $150 billion in the fiscal year that began Oct.1, could thwart a recovery. ''I think there is more room for debate on the military side than is being given,'' said Philip Caldwell, chairman of the Ford Motor Company. ''People ask us about the quality of our products. Well, it's a fair question to ask the Government about the quality of its products.''

A senior New York State official said yesterday that state tax collections were falling sharply because of the recession. Unless new taxes are enacted by the Legislature, he said, the state could end the fiscal year with a deficit of more than half a billion dollars. The official said that new data on collections during the first six months of the year had shown a sharp drop in receipts from personal income, and sales and business taxes. As a result, he said, revenues for the year are expected to decline by between $200 million and $300 million beyond previous estimates.