Former Arkansas Gov. Mike Huckabee argued Tuesday that Donald Trump needs to quit attacking his critics and instead "land his punches" on Hillary Clinton.

"Look, Donald Trump has got to focus on the people of America, not on whatever slights are said about him," the ex-White House hopeful told Fox Business. "Think of it as a boxing match. [Trump] is the boxer in the ring [and] he needs to land his punches on Hillary, not the guy in the front row who is yelling at him and heckling him, because that's not his opponent."

Huckabee urged Trump to focus on highlighting Clinton's shortcomings and "unleashing" his anger over Americans' "loss of jobs, their loss of wages, for the trade deals that have gone wrong [and] for the total bungling of our foreign policy."

"If that's what he's fighting, let him go unfiltered," Huckabee said. "Let him say it like he wants to, let him go to the podium and take on everything from open borders, illegal immigration because that's what got him here.

"But when [Trump] starts taking on individuals who aren't part of process, then he gets himself distracted," the former governor conceded.

"His opponent isn't Warren Buffett. It's not the father of Capt. Khan. He needs to leave that stuff alone," Huckabee said. Buffett has been berating Trump recently for refusing to release his tax returns, while Trump has been feuding with Khizr Khan, the father of Capt. Humayun Khan, a Muslim-American soldier killed in Iraq.

"[Trump] needs to fight for the people and he needs to fight the right opponent and her name is Hillary, and that's where he's got to put his punches," Huckabee advised.

"When this whole thing with Capt. Khan came up, he should have affirmed the sacrifice and the service of this incredible man who died for his country. But then he should have said this: No. 1, who killed Capt. Khan? Radical Islamists. No. 2, who voted for the war that he was in? Hillary did. Donald trump opposed it.

"He should have made those two points and then left it alone," Huckabee said.