With Rick Perry out of the Republican race for president, Donald Trump on Saturday focused his barbs on another opponent in the crowded field of primary candidates, retired neurosurgeon Ben Carson.

In polls in national and early-voting states, Carson is second only to Trump. He recently cast doubt on the real estate mogul’s religious faith, questioning his “fear of the Lord,” then backed off the comment and would not repeat it.

“You don’t hit a person on faith,” Trump told hundreds of people at a rally in Boone.

“I don’t know him. He knows nothing about me. I’m protestant, I’m Presbyterian, I believe strongly, believe in the Bible strongly. But he hit me on my faith. No, I believe strongly. You don’t hit a person on faith. And he was nice enough to apologize.”

Trump, who has made a practice in public appearances and interviews of listing those he says have wronged him, told the crowd that he doesn’t think Carson could negotiate effectively with world leaders.

“I don’t think Ben has the energy,” Trump said. “Ben is a nice man, but when you’re negotiating against China and you’re negotiating against these Japanese guys that are going to come against you in waves, and they think we’re all a bunch of jerks ’cause our leaders are so stupid and so incompetent and so inept, we need people that are really smart, that have tremendous deal-making skills and that have great, great energy.”

Trump traveled to Ames, where Iowa State hosted rival Iowa for a football game that is one the state’s largest single-day gatherings. Although he had been scheduled to mingle with tailgating fans outside of Jack Trice Stadium and talk at the Iowa Republican Party tent, he instead went inside the stadium to meet with Iowa State President Steven Leath. He later posed for photos with fans and cheerleaders as he walked around the field’s perimeter.

Three other Republican hopefuls met with tailgating fans — Wisconsin Gov. Scott Walker and Sens. Rand Paul of Kentucky and Marco Rubio of Florida.

Walker waded through the throngs of crimson-wearing Iowa State Cyclone and black-and-gold-clad Iowa Hawkeye fans, unrecognized by many. Ben Larsen, who drove three hours from Blair, Nebraska, to see candidates, shook Walker’s hand and smiled, though he later said, “I’m more a Rubio guy.”

Hours earlier, Rubio told reporters that Perry “is a good man” and “I’m sure he’s not done serving our country.” A day earlier, Walker made a more public pitch for Perry’s supporters while campaigning in eastern Iowa.

Perry said Friday evening that he was suspending his campaign.

(AP)