This hardworking man's incredible surprise for his grandparents will make you want to pick up the phone and call grandma and grandpa.

Stefun Darts, a 24-year-old who lives in Houston, Texas, shocked his grandparents, Cecil and Marilyn Roberts, earlier this month, when he presented them with a $15,000 check to pay off their mortgage, according to People.com.

The incredible moment was captured in an emotional YouTube video and there's really no way you won't be crying along with everyone in the clip.

"The best and most beautiful things in the world cannot be seen, nor touched ... but are felt by the heart," Darts wrote on his Facebook page. "Even with this, I could never repay you for what you've done for me."

Watch in the video as Darts' grandparents start off in shock at what the 24-year-old, who's a San Jacinto College student and founder of the nonprofit Caring Heart Youth Foundation, has done for them. When Darts' good deed sinks in, the entire room dissolves into tears with his grandparents are clearly overcome with joy.

According to ABC News, the Roberts' have done a lot for Darts and his family. Seeing his grandparents work so hard had a big effect on him.

"I couldn't stand you going to work at night," he wrote in a Facebook post. "Some nights I didn't even sleep knowing it shouldn't be like this."

When Darts was only in second grade, he made a big commitment.

"I promised God in the second grade I would pay off your guys' house and help you retire. A promise I would never break," he wrote on Facebook.

So Darts devoted himself to fulfilling that promise. The 24-year-old took on various odd jobs for the past six years, ABC News reported. He also gave up some fun so he could eventually surprise his grandparents.

“I’ve been eating pizza, microwave pizza for all my life,” Darts explained to KHOU of the various sacrifices he made to help his grandparents. “My friends will tell you I never did go out. They didn’t know, but this was the reason why.”

So the 24-year-old was ecstatic when he finally presented his grandparents with the check to pay off their mortgage -- something that would've taken them another four years. To top it all off, Darts also hooked them up with a trip to the Bahamas.

Judging by the Roberts' reactions, their grandson's generosity and selflessness surely paid off.

“I couldn’t believe it,” Marilyn said, according to KHOU. “To have a grandson like that is a blessing.”