Bush, who defeated McCain for the 2000 Republican presidential nomination, called McCain a "man of deep conviction and a patriot of the highest order" and a "friend whom I'll deeply miss". "I always thought of John as a brother", Biden said.
Senator McCain will lie in state at the United States Capitol in Washington, D.C.
McCain died Saturday after battling an aggressive form of brain cancer.
Among the speakers on Thursday was Grant Woods, McCain's former chief of staff, who retold one of the earliest anecdotes from the epic that was the senator's life.
One by one, McCain's family and then his friends and colleagues approached the coffin to say goodbye.
Arizona Cardinals wide receiver Larry Fitzgerald Jr. - who became friends with McCain after his National Football League career began, and who recently wrote a piece for Sports Illustrated on his admiration for McCain's service in Vietnam - is also slated to give remarks.
A light rain fell as McCain's casket was carried into the Capitol by members of America's military services.
"While from very different worlds, we developed a meaningful friendship", Fitzgerald said.
The church's senior pastor, Noe Garcia, pronounced McCain "a true American hero".
"I said I've got two purple hearts, too".
Biden, a Democrat, praised McCain as a lawmaker and war hero who placed his belief in America above politics and partisanship. And he spoke directly to McCain's widow, Cindy McCain, seated in the front row: "You were his ballast".
This is probably what the next Apple Watch will look like
There's also been chatter of a new iPad Pro , for instance, and indeed refreshes elsewhere in Apple's hardware line-up. Notably, all new iPhone models are expected to have edge-to-edge displays, gesture controls, and FaceID.
Google overhauls Wear OS to up the ante against Apple
This major redesign is rolling out as part of a Wear OS update , with watches receiving the new features over the next month. Just as with the notification droplist in Android, by tapping many listings, you get options as to what to do next.
A Peek Inside A Teen Prince Harry's Eton College Dorm Room
Taken when he was only 18, the photos showcase Prince Harry's day-to-day life while he was still in boarding school. He even kept a sweet black-and-white framed portrait of his late mother on his desk.
As always, there was plenty of ribbing about the senator, who was known for his passionate politics and often stubborn personality.
McCain's family asked before his death that President Donald Trump, who the senator had long feuded with, not attend his funeral services.
Defence Secretary James Mattis greeted the McCain family Thursday night when the late senator's casket was flown into Joint Base Andrews, Maryland. Twenty-four sitting USA senators, four former senators and other leaders were among those expected at Thursday's memorial.
McCain is survived by his wife, Cindy McCain, and his seven children: John, Andy and Sidney McCain, from his first marriage to Carol McCain; as well as Meghan, Jack, Jimmy and Bridget McCain from his second marriage.
McCain will lie in state in the Capitol Rotunda on Friday before a motorcade will take him the the National Cathedral on Saturday, with the former Vietnam prisoner of war passing by the Vietnam Memorial on the way.
A few firefighters saluted from atop a fire engine parked on an overpass as the motorcade passed underneath on Interstate 17. Your love set an example for all of us to follow.
The Capitol was then opened to the public Wednesday afternoon, allowing visitors to walk by the flag-draped closed casket after waiting in line outside in the temperatures that reached a high of 104 degrees (40 Celsius).
A choir from the Jesuit-run Brophy College Preparatory school that two of McCain's sons attended was scheduled to sing "Amazing Grace" and "Arizona" during the church service.
Ahead of the service Thursday morning, the line for people with tickets to sit in the public section wrapped halfway around the block-sized church. It was about a prison guard in Vietnam who showed McCain unexpected kindness by loosening the painful ropes around his wrists and, much later in his imprisonment, drawing a cross in the dirt for him as a sort of Christmas gift.
"He ran for president; I run out of bounds", he said, drawing chuckles from the people sitting in the pews.
McConnell, a man who at times fought on the opposite side of McCain on issues such as campaign finance, remembered him on the Senate floor earlier this week as a tough political opponent.