“Sometimes we don’t need a miracle. We just need people to do what they said they would.”

Alex Sheen, founder of the charitable nonprofit Because I Said I Would, said that to the audience during an NAPT Summit general session on Monday as he shared the story of what led him to create it: a message he posted online that went viral right after he lost his father to cancer three years ago.

Sheen recounted his father’s struggle with his illness, and recalled how the one thing he admired the most about his dad was that if he said he would do something, he did it.

“’Alex, your lacrosse game is at 7:00?’ 6:59, he would be in the stands,” Sheen said.

In the post that went viral, Sheen said that he would send 10 “promise cards” for people to write a promise on to anyone in the world for free. At the bottom, the cards said “Because I said I would.” At first he received about five requests per day, but that soon grew into the thousands. Since 2012, his nonprofit has delivered more than 3.5 million cards to a total of 153 countries. At first he was bewildered by the fact that so many people around the world wanted the cards even though the words were in English. The idea spread like wildfire because the concept of keeping a promise is universal, he said.

“It doesn’t matter what language you speak,” he said. “In any culture, you’ll find the importance of a promise.”

People posted their promises online. They ranged from being very serious, as with a man diagnosed with stage 4 cancer of the kidneys, who promised to write 826 more notes of encouragement to place in his daughter’s lunchbox, so she’ll still receive them until she graduates high school even if he passes away before then, to the more lighthearted, like one from a man who promised to take his Christmas lights down before Easter.

Then, Sheen said, there was one from a girl who promised to join kids in her school who were sitting alone at lunch. It turns out that three students had committed suicide in her school after they were bullied.

“’She wasn’t sure what she could do,” he said. “She thought, ‘It may be small, but at least it’s something.’ This is about doing what you can with what you have.”

Sheen added that he receives thousands of messages with powerful stories every day, with one of the most powerful being the one that ended up being the impetus for him to quit his job earning six figures and devote more of his time to charity work.

He received a letter from a young girl who was depressed and was planning to commit suicide, and was cutting herself, but the promise cards made her realize how many people she had in her life that cared about her.

He brought the letter to show to his boss, to help her understand why he needed to pursue his cause. The letter turned out to be from her daughter.

Sheen described Because I Said I Would as “a social movement and a nonprofit dedicated to the betterment of humanity through promises made and kept.” The organization has taken on such charitable projects as driving through the night to bring food and other essentials to victims of Hurricane Sandy, cleaning up after the riots in Ferguson, Missouri, and raising the money to send 20 children with cancer to Disneyland with their families in 2013.

Also in 2013, Sheen walked 240 miles across Ohio in 10 days to raise awareness of sexual violence in response to the news of three women who were imprisoned, raped and abused in a home in Cleveland just six miles away from where he lived. He said that during this walk, he was alone about 95% of the time.

“We want people to show up with us, but when they don’t, we have to go it alone,” he said.

Sheen added that what kept him from giving up on the walk was remembering the reason he started in the first place: abuse survivors Amanda Berry, Gina DeJesus and Michelle Knight.

“If you have a strong reason why, then you can be strong,” he told the audience.

As its next step, Because I Said I Would will start chapters, called Echoes, all across the U.S. in 2016 to head up various charitable projects.