Vice President Joe Biden sat down with Stephen Colbert yesterday for an emotional interview where he reflected on the loss of his son, Beau, and expressed doubt about a bid for president.

Biden said that all presidential candidates should be able to look at Americans and say, “I promise you, you have my whole heart, my whole soul, my energy and my passion to do this.”

“I’d be lying if I said that I knew I was there,” he admitted.

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The vice president remarked that he doesn’t think anyone has the right to run for president “unless they’re willing to give it 110 percent of who they are.” He explained how losing Beau can overwhelm him, recalling a recent trip to a Colorado military base.

“It was going great, and a guy in the back yells, ‘Major Beau Biden. Bronze Star, Sir. Served with him in Iraq.’ And all of a sudden, I lost it,” he said.

Biden said that Beau asked him to promise that he would be alright just months before he died. He also talked about the “enormous sense of solace” that his faith has given him.

The vice president recalled one of his mother’s favorite expressions: “As long as you’re alive, you have an obligation to strive, and you’re not dead until you see the face of God.”

He said that message has been imbued in him, and that you have to get up every day and put one foot in front of the other even after losing someone.

Biden and Colbert also touched on the “Late Show” host’s own loss; Colbert’s father and brothers were killed in a plane crash when he was just 10 years old. Colbert said that he always joked that he raised his mother after that, and Biden said that his sons “honest to God” raised him, too.

Watch the full interview below.