“Apple would not exist without immigration,” Cook told them while receiving an honorary doctorate, according to CNBC. “This is a huge issue for us … we stand up, we don’t sit in silence.”

“Steve was the son of an immigrant,” Cook said. “Our company has immigrants in it that are key to the innovation of our company. Our company depends on diversity … diversity of thought, and people generally have diverse views … it’s the tapestry of getting people with all different backgrounds and all different point of views that are able to create the best products.”

Jobs’ biological father, Abdulfattah Jandali, was born in Syria—a country from which President Trump’s executive order has indefinitely barred immigrants. And he’s not the only founder of a major tech company whose parents were born outside the U.S. or who came here themselves: Tesla’s Elon Musk, Google’s Sergey Brin, and Amazon’s Jeff Bezos all have overseas connections.

During his speech Thursday, Cook repeated his criticism of the president’s immigration ban, and talked about Apple employees whose families were affected.

“They couldn’t get back in,” he said. “That’s a crisis. You can imagine the stress.”