The Jewish phrase Tikkun Olam means to repair the world through acts of kindness. It’s a concept Leonard and Roslyn Stoler say they model their life on.

After achieving financial success from a chain of automobile dealerships, the Stevenson residents and owners of Len Stoler Automotive Group have become prolific philanthropists, giving tens of millions of dollars to causes dear to their hearts, mostly having to do with cancer.

The couple’s names grace a building at the University of Maryland Medical Center, where they became the top donors after a $25 million gift, the largest donation in hospital history, to build a new facility to house the Marlene and Stewart Greenebaum Comprehensive Cancer Center. The couple, married 59 years, gave $5 million to the medical center in 2003 for construction of an outdoor pavilion at the cancer center. A chemotherapy robot that dispenses drugs at three times the rate of a pharmacist also came courtesy of $1.2 million donated by the Stolers.

The couple’s relationship with the hospital was sowed 27 years ago when their granddaughter Lindsay was treated for cancer at age 4. Hospital officials said the Stolers’ involvement goes far beyond writing a check and that they are hands-on donors who visit the hospital frequently.

“They are just the most genuine and caring individuals you could meet,” says Dr. Kevin J. Cullen, director of the cancer center. “Their message is, ‘How can we help you do things better? How can we help you serve your patients’ better?’ They have no ego. They have no expectation of any sort of special gratitude or special treatment. They see themselves as having been very fortunate in their lives and want to give back.”

While the Stolers look at benevolence as part of their mission in life — just as the Jewish mantra proclaims — they also say they feel a genuine gratitude when they are able to help others.

“When we give money we get back so much more than we give,” Ms. Stoler says.

If it wasn’t for a buddy who convinced Mr. Stoler to help him sell cars, he and his wife, who met on a double blind date, might not be in a position to be so charitable. He took the job only after much convincing from his friend and because he had just returned home from the military and didn’t plan on enrolling in college until the following year.

“The last thing I wanted to do was to be a used-car salesman,” he says.

He soon learned life sometimes takes an unexpected turn. To his surprise, Mr. Stoler had a knack for convincing people to buy a vehicle and would never make it to the Johns Hopkins University, where he had once planned to study electrical engineering. He opened his first dealership in 1968in Dundalk with the help of a $5,000 loan from his wife’s aunt.

What started off as one 7,500-square-foot dealership with nearly two dozen employees has grown into a chain of dealerships — with nine locations in Maryland and three in New York — that employ hundreds of people.

The Stolers’ charitable and civic involvement goes well beyond the University of Maryland Medical System. Ms. Stoler is on the board of the Mt. Washington Pediatric Hospital and its affiliated foundation where the CEO says she takes a hands-on approach with the patients. During the holiday season she often personally delivers gifts to the children in the hospital.

“She would show up with an SUV filled with gifts,” says Sheldon Stein, president and CEO of the children’s hospital. “She has a passion for what these children need and quietly and very unassuming and without any fanfare at all does what she can to make sure they get it.”

The couple’s recent donation to the University of Maryland Medical System will allow cancer patients to get all of their treatment in one building, rather than throughout the hospital as is the case now. They hope this makes treatment more comfortable for patients.

“They are very passionate about their work and what we do here and really think about the patient experience,” says Janice Eisele, the medical system’s senior vice president of development. “It is a scary time. It is a scary time for patients, and they saw that firsthand with their granddaughter.”