The Detroit medicine professor has given out more than 6,000 free lessons to kids with cancer and other diseases

Rabbi Elimelech Goldberg will always remember his toddler’s bravery after she fell ill with leukemia.

Diagnosed in 1980, Sara Goldberg would routinely tell her fellow young patients, “Don’t cry,” her father says. And she would reassure him by saying, “It’s okay, Daddy.”

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Sara died at age 2. “Thirty-one years later,” says her father, “I still cry.”

It’s the memory of Sara’s courageous battle that drove Goldberg to found Kids Kicking Cancer, a nonprofit dedicated to providing children with cancer and other serious diseases with free lessons in martial arts, breathing techniques and meditation.

To date Goldberg, 56 – a black belt in Choi Kwon Do who teaches at Wayne State University School of Medicine in Detroit – has provided free classes to 6,100 children. Since March 2012, Kids Kicking Cancer has also expanded with programs in Israel, London, Ontario, Italy and New York.

“When you see a child gain the ability to do this for themselves, and then see them light up, in the midst of all this darkness – it’s the most beautiful light in the world,” says Goldberg.

Aside from mastering kicks, Goldberg’s students also hone skills they say help them cope off the mats.

“Power-breathing helps you push out the pain and anger,” says Desireé Smith, 12, “and let in the good.”

In remission for about a year and a half, leukemia survivor Sara Budzynski, 15, (who has put together a fundraiser for Kids Kicking Cancer) says that she is “forever thankful” for the program and shared with PEOPLE the top lesson she picked up along the way.

“The biggest thing I’ve learned?” she says. “Not to give up.”

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