A similar impulse motivates me now as I witness the present vitriol and divisiveness in America, just as it did when I spoke out against President Trump’s travel ban earlier this year. I said that his directive, which prohibited travel from several majority-Muslim nations, doesn’t reflect the values Pat died for or those of his namesake foundation. Established by those of us closest to Pat after he died in Afghanistan in 2004, the Pat Tillman Foundation recognizes and helps other patriots who stood up when it was much easier not to.

I’ve been thinking about one of them a lot lately, too: a Marine and Tillman Scholar named Adrian Kinsella, who the foundation helped put through law school and whose story is a lesson for the current moment. While serving in Afghanistan, he grew close with an interpreter named Mohammed. When his tour was over, Adrian found he could not sit comfortably at home while Mohammed remained vulnerable to the Taliban because of his work. “I bonded with him because when I was young I could relate to his same background, struggling as a kid and wanting to make a better life for yourself and your family,” Adrian said in an interview last year. “Mohammed has a work ethic like that of a Marine.”

Adrian sought our help during his more than three-year-long effort to bring his friend to the United States; the Tillman Scholar community wrote letters to Congress on Mohammed’s behalf, and some took leadership roles in organizing support efforts. Ultimately Adrian’s work paid off: Mohammed arrived in 2014. His family, which was also at risk, arrived months later, following a national campaign that NBC News reported “spanned senators and congressional members, TV comedian John Oliver, plus experts in immigration law, web design, and social media.” I’m proud of Adrian, and I’m proud that the foundation’s community played a part, however small, in helping him. I can think of no better way to honor Pat, who would have felt the same way about someone like Mohammed as Adrian did.

But their story, like Pat’s story, also serves as a reminder that Americans cannot be spectators when it comes to matters of justice. Adrian fought for Mohammed because, he said, “there was really no other choice,” and Mohammed risked his life to help a nation that wasn’t yet his own. Neither let fear dictate how they treated one another—a lesson the country and its leaders would do well to consider now.

Fear is what keeps people from engaging in dialogue with those who are different and prevents them from recognizing shared humanity. Fear of the unknown is what slams the nation’s doors—hard—on those seeking the American dream, whether they are injured veterans hoping to reintegrate into their communities or immigrants searching for opportunity. The reverberations from those impacts can be more long-lasting than they seem, and they put cracks in the foundation of democracy that aren’t easily patched up.