During the interview, Biden also said that he had "no desire" to become a Supreme Court justice.
Biden was asked if someone who wants to build a wall, “by definition, isn’t a Christian,” as the pope suggested in recent remarks.
“Well I am not a theologian nor am a priest or minister but I think building walls is fundamentally contrary to what made this country what it is,” Biden responded.
Trump has blasted the pope's remarks, calling them "disgraceful."
"If and when the Vatican is attacked by ISIS, which as everyone knows is ISIS’s ultimate trophy, I can promise you that the Pope would have only wished and prayed that Donald Trump would have been President because this would not have happened," Trump said in a statement. "ISIS would have been eradicated unlike what is happening now with our all talk, no action politicians."
The vice president said it's "very possible" Trump wins the GOP nomination, but he would be "surprised" if the real estate mogul won the general election.
"I think it is very possible he could be nominated and depending on how this all plays out, I would take him seriously in terms of being able to win because he's appealing to a very, very -- he's appealing to fear," Biden said. "He's appealing to, that whole expression, everybody who asked me, why is Trump able to win in those 16 people?"
"There's a whole expression. In the land of the blind, the one-eyed man is king," he said. "I'm not very good at prognosticating but I would not be surprised if he's the nominee. I would be surprised if he got elected."
Biden also weighed in on the battle brewing over the Supreme Court as President Obama determines who he will nominate to fill Justice Scalia's seat. He criticized Republicans for suggesting President Obama shouldn't nominate a replacement.
“I think because they're intimidated by -- by the dominant element of the Republican Party, the national politics right now, the far right. I think they're intimidated by it. I think it's the tail wagging the dog," Biden said. "I think the leadership went out to make sure they got out ahead of Ted Cruz. I don't believe in their heart they think this makes sense. We've never done this before."
"If we don't nominate someone in the next month or so, start the hearing process. And they say nothing's going to happen until the next election. It won't be until next June or July before you have a Supreme Court justice," he added. "We have a dysfunctional Congress now. We don't need an institutionally dysfunctional Supreme Court."
Biden said he thinks the president could choose a "consensus candidate" for the Supreme Court. Asked how he would respond if President Obama asked him to serve, Biden said he had "no desire" to be a Supreme Court justice.
"I have no desire to sit on the Supreme Court, none. It would be a great honor," he said when asked what he would say if President Obama asked him to replace Justice Antonin Scalia. "I have no desire, any more than George Mitchell did."
Biden did preface his answer with this important caveat though -- "You never say to a president for certain you wouldn't do anything."