Walz-Vance debate updates: VP candidates tangle on abortion, immigration and Jan. 6

Walz repeatedly poked at Vance's past criticisms of Trump and now the CBS moderator is asking him to explain

"Because I've always been open and sometimes, of course, I've disagreed with the president but I've also been extremely open about the fact that I was wrong about Donald Trump," Vance said.

Vance blamed the media for its coverage of Trump and then said he changed his mind in part because of Trump's record in office.

Both candidates were asked how their economic plans would avoid ballooning the deficit by trillions of dollars, citing projections by the Wharton School.

Walz said their plan is "simple."

"Kamala Harris has said to do the things she wants to do, we'll just ask the wealthiest to pay their fair share. When you do that, our system works best, more people are participating in it, and folks have the things that they need," he said.

Vance pushed back against the analysis.

"A lot of those same economists attack Donald Trump's plans, and they have PhDs, but they don't have common sense and they don't have wisdom," Vance said, citing Trump's record on tax cuts.

The Penn Wharton Budget Model has estimated that Trump's tax and spending proposal will cause tax revenue to fall by $5.8 trillion and produce a similar amount of primary deficit over the course of a decade.

Vance lashed out at the experts, saying not to trust them but to trust "common sense."

"A lot of the same economists attacked Donald Trump's plans and they have PhDs but they don't have common sense and they don't have wisdom," he said.

Walz immediately pushed back on Vance.

"Economists can't be trusted. Science can't be trusted. National security folks can't be trusted. If you're going to be president, you don't have all the answers. Donald Trump believes he does. Pro-tip of the day is this, if you need heart surgery, listen to the people at the Mayo Clinic in Rochester, Minnesota, not Donald Trump," Walz said.

Walz has never invoked his Christian faith on the campaign trail, but during the debate, he quoted a Bible verse while reiterating his support for the border bill that failed to pass through Congress this year.

“This bill gets it done in 90 days. Then you start to make a difference in this and you start to adhere to what we know, American principles. Look, I don't talk about my faith a lot, but Matthew 25:40 talks about -- to the least amongst us. You do unto me," he said.

"I think that's true of most Americans. They simply want order to it. This bill does it. It's funded. It's supported by the people who do it. And it lets us keep our dignity about how we treat other people,” he said.

-ABC News' Isabella Murray