September 9, 1982

Three Lutheran denominations voted today to form a new church for 5.5 million members that will be the third largest Protestant denomination in the country. Dr. Martin Marty, a church historian at the University of Chicago, said that the action marked a 'decisive point' in American church history and that there had never before been such a merger in an American denomination. The merger brings together three of the five major Lutheran denominations in the United States. The denominations have a common theology but diverged according to the countries from which Lutheran immigrants came here.

Last Thursday night, as police officers and other emergency personnel watched from below, Edward McGuire grabbed and wrestled to safety an 18-year-old man threatening to jump from the roof of a six-story apartment building here. Many of those who watched the ordeal and others who heard about it are calling Mr. McGuire's action ''heroic.'' But the Larchmont police are calling it an ''obstruction of governmental administration'' - a misdemeanor punishable by one year in jail or a fine of $1,000, or both.

Cautious American consumers took on only $570 million more in installment debt than they paid off in July, the smallest debt increase since February, Government figures showed today. The Federal Reserve Board report covered the first month after the Reagan Administration's big tax-rate cut took effect on July 1. Businessmen and Government officials have been hoping the cut would help generate a surge in consumer spending that would pull the economy out of a year-long recession. But most economists said they did not expect big spending increases to show up immediately.

The stock market tried to resume its late summer rally yesterday after Tuesday's sharp sell-off but managed to close with only small gains in very heavy trading. The Dow Jones industrial average finished the session up 1.47 points, to 915.75. On Tuesday, profit taking sent the Dow down 10.85 points after the key indicator had soared 148 points, or 19 percent, in the previous 16 sessions. Stock exchanges were closed Monday in observance of Labor Day.

Chemical Bank, in one of the first announcements of its kind, said yesterday that it would introduce a service that would allow its customers in the New York area to bank at home using personal computers. Such home electronic banking has been the subject of numerous market tests, but Chemical, the nation's sixth-largest bank, would be the first of the nation's largest banks to offer such a service commercially. Customers using the system would be able to do such things as keep track of their checking accounts and home budget, transfer money from one account to another and pay bills electronically by typing commands on the computer keyboard. Mark Plakias, research director for Link Resources Corporation, a New York market research firm, said that as home banking, shopping and other electronic services achieved commercial status, other companies were likely to follow Chemical. Its move ''indicates the consumer is much more ready to use this kind of a product than most people imagine,'' he said.