Former Vice President Joe Biden delivered an emotional tribute on Thursday to his longtime friend John McCain, lauding the late senator for his service to the country and his commitment to the “basic values” of America.

“There’s nothing anyone can say or do to ease the pain right now,” Biden said to McCain’s family during the funeral service in Phoenix. “But I pray you take some comfort knowing that because you shared John with all of us your whole life, the world now shares with you in the ache of John’s death.”

Before his death, McCain asked Biden—who, alongside Barack Obama, ran against McCain in the 2008 presidential election—to deliver the eulogy at his funeral. Obama will do the same at McCain’s memorial service at the National Cathedral in Washington, D.C., on Saturday.

“I always thought of John as a brother. We had a hell of a lot of family fights. We go back a long way,” Biden said, referring to their decades of service together in the U.S. Senate. “Above all, we understood the same thing. All politics is personal. It’s all about trust. I trusted John with my life.”

McCain died on Saturday after a battle with brain cancer, the same disease that took the life of Biden’s son, Beau, in 2015. Their mutual friend, the late Ted Kennedy, also died from the same type of cancer. “It’s brutal. It’s relentless. It’s unforgiving,” Biden said of the disease.

The former vice president and longtime senator, who is rumored to be considering a presidential run in 2020, held back tears as he addressed McCain’s family in the front row at North Phoenix Baptist Church.

He lamented the state of American politics today, saying that people attack each others’ “motives, not the substance of their arguments.” In what many viewed as a symbolic rebuke of President Donald Trump, Biden said McCain would only “part company with you ... if you lacked the basic values of decency, respect. Knowing that this project is bigger than yourself. ... Giving hate no safe harbor. Leaving no one behind. And understanding as Americans we’re part of something much bigger than ourselves.”

McCain’s longtime friends Grant Woods and Tommy Espinoza, in addition to Arizona Cardinals star Larry Fitzgerald, also paid tribute to the late senator. More than two dozen current and former senators were in attendance. Immediately after the funeral, McCain’s casket was taken by motorcade to Phoenix Sky Harbor International Airport, where it will be flown to Joint Base Andrews, outside Washington. On Friday, McCain will lie in state in the U.S. Capitol rotunda.

Near the end of his speech, Biden addressed McCain’s immediate family again and explained to them why the entire country, and the world, was so deeply affected by McCain’s death.

“I think it’s something more intangible. I think it’s because they knew John believed so deeply and so passionately in the soul of America. That he made it easier for them to have confidence and faith in America. His faith in the core values of this nation made them somehow feel it more genuinely themselves,” Biden said. “His belief, and it was deep, that Americans can do anything, withstand anything, achieve anything, was both unflagging and reassuring that this man believed it so strongly.”

“To paraphrase Shakespeare: we shall not see his like again.”