When he was 4 years old, his mother found him in the kitchen with a knife. He was summoning the nerve to slice off his fingers. This wasn’t because he was crazy but because he was all too sane and understood correctly the dysfunctional appendages dangling from his misshapen left hand were the source of his physical agony. He wanted relief.

The very next day she scheduled the operation she knew he might need. There was no avoiding it anymore. The surgeon cut near the wrist, amputating everything below, and soon the boy returned home to figure out the rest of his life.

He did that by changing nothing about his dreams. He wanted to play football, so he played football, just like his twin brother, except not just like his twin brother, because his brother had an extra tool — an extra hand — that he didn’t. No matter. He compensated. He adjusted. What he lacked in reach and grip he made up for in grit and speed.

He impressed many people. He repelled some. When he was 8 years old, the coach of a rival team tried to keep him off the field, first claiming he had weighed in too heavy for the game and then admitting a different reason. Football, he told the boy, was for people with two hands.

He grew into a high school football star in Florida, became a starting linebacker for the University of Central Florida. Minus one hand, he intercepted balls and recovered fumbles. He was drafted to play linebacker for the Seattle Seahawks this season.

That’s Shaquem Griffin’s story, and it’s the inspiring tale we need. In this rancorous country, we’re buffeted more than usual by reminders of humanity at its worst. Griffin is a glimpse of our best — of our ability to reframe hardship as challenge.

He never dwelled on the cause: amniotic band syndrome, by which fibrous strands of the amniotic sac wrap around a portion of the developing fetus, strangling development.

His rookie season got off to a rocky start. Many rookie seasons do. In the Seahawks’ first game, against the Denver Broncos on Sept. 9, he made mistakes. In the team’s second, against the Chicago Bears on Monday, he sat on the bench.

Along with Colin Kaepernick and Serena Williams, among others, he was recently chosen by Nike as one of six new “changemakers” for its Just Do It campaign. He appears in the campaign’s glorious “Dream Crazy” commercial.

It’s narrated by Kaepernick, who at one point says: “If you have only one hand, don’t just watch football. Play it — at the highest level.” The images with those words are of Griffin sprinting like lightning, wrestling an opponent to the ground and spreading his asymmetrical arms wide in triumph in the middle of the field.

If that doesn’t move you, how about this? That twin of his, Shaquill, refused to go to any college that didn’t also want his brother as part of a package deal. They attended UCF together. They hate being apart, and they aren’t. Shaquill was also drafted by the Seahawks, to play cornerback.

Shaquem Griffin, 23, understands the power of his example. He welcomes it. “I feel like all the boys and girls out there with birth defects — we have our own little nation, and we’ve got to support each other,” he wrote in The Players’ Tribune.

Citizens of that nation showed up for the Denver game to watch Griffin’s big NFL debut. An article by Robert Klemko in Sports Illustrated noted how visibly emotional they were and how they swarmed Griffin’s mother, a nurse, who was there, beaming, on the sidelines. Klemko contemplated Griffin’s swelling ranks of fans and the games to come, predicting: “They won’t just be amputees, the ones who weep. They’ll be mothers and fathers. And nurses too.” And me. I agree with Griffin: This isn’t a sad story. But it’s most definitely a sob story.

— Frank Bruni is a columnist for The New York Times.