Facebook chief Mark Zuckerberg choked up while speaking about an illegal immigrant “DREAMer” during his Harvard commencement speech and declared that the fight against the forces of nationalism “is the struggle of our time.”

Zuckerberg acknowledged on Thursday that “there are people left behind by globalization across the world” and even conceded that “there are people in every country for global connection and good people against it.”

“It’s hard to care about people in other places if we don’t feel good about our lives here at home,” he said. “There’s pressure to turn inwards.”

He then said, though, that the struggle of our time will be between “the forces of freedom, openness and global community against the forces of authoritarianism, isolationism and nationalism.”

“Forces for the flow of knowledge, trade and immigration against those who would slow them down,” he continued. “This is not a battle of nations, it’s a battle of ideas.”

Zuckerberg then choked up as he told the graduates that one of his top students at the Boys and Girls Club where he volunteers his time was a DREAMer who “raised his hand and said he wasn’t sure he could go [to college] because he’s undocumented. He didn’t know if they’d let him in.” Zuckerberg said he took him out for his birthday and when he asked him what he wanted, “he started talking about students he saw struggling and said, ‘you know, I’d really just like a book on social justice.’”

He said he was “blown away” because “here’s a young guy who has every reason to be cynical. He didn’t know if the country he calls home—the only one he’s known—would deny him his dream of going to college. But he wasn’t feeling sorry for himself. He wasn’t even thinking of himself. He has a greater sense of purpose, and he’s going to bring people along with him.”

“It says something about our current situation that I can’t even say his name because I don’t want to put him at risk. But if a high school senior who doesn’t know what the future holds can do his part to move the world forward, then we owe it to the world to do our part too,” he said as he started to tear up.

Zuckerberg’s political advocacy group, FWD.us, called then-candidate Donald Trump’s immigration plan “absurd” while unsuccessfully lobbying for amnesty legislation and an unlimited number of H-1b visas for the technology industry to import more foreign workers to displace Americans.

Zuckerberg’s commencement address also made waves because he said “we should explore ideas like universal basic income to give everyone a cushion to try new things.”