Take a break. It's called "Labor Day" - but it's a day when most people don't work. It happens every year on the first Monday in September, to honor members of the nation's work force. And it will be celebrated tomorrow by more employed Americans than any other time in the holiday's long history. Labor Day, which became a legal holiday by an act of Congress in 1894, has provided an end-of-summer respite since 1882. In that year, the first observance was held in New York under the aegis of the New York Central Labor Union.

Healthy progress. Organizers of that first Labor Day parade would be justifiably proud of the great strides our labor force has made during the intervining century. In 1880, there were just 14.7 million workers in the country. Today, the nation's labor force is over the 100 million mark; nearly 60 percent of all Americans age 16 or older are now gainfully employed.

People power. During the 1960s, it was popular in certain academic quarters to envision a future in which the human factor in America's work force would yield its role to computers and machines. But the specter of machines idling millions proved to be a myth - like so many other predictions of gloom and doom. The nation's business and industry have added 16 million workers to their payrolls since 1970, and in April of this year alone, 535,000 Americans found work. The index of help-wanted advertisements - a traditional measure of the nation's economic well-being - is the highest since tabulations began 27 year ago. Unemployment is still a cause for serious national concern. But there are parts of the country with significant labor shortages in certain professional, technical and skilled trades areas.

Sharing the load. The growth and prosperity of the nation's industries have made it possible for today's work force to reach its present size and strength. The Mobil employment in this country for some 150,000 people - more than three-quarters of its worldwide total. (Worldwide, the Mobil companies' bill for wages and benefits last year amounted to nearly $3 billion.)

A quote we like, ". . . despite the clamor which we hear, and the conflicts which occasionally occur, there is a constant trend toward agreement between the laborers and capitalists, employed and employer, for the uninterrupted production and distribution of wealth . . ." Samuel Gompers.