CLEVELAND -- New Jersey Gov. Chris Christie tore into Ted Cruz after the U.S. senator failed to endorse Republican presidential nominee Donald Trump Wednesday night at the Republican National Convention.

"I think it was awful, and quite frankly, I think it was selfish," Christie told CNN about Cruz's speech shortly after the Texas lawmaker walked off the stage to loud boos.

Christie and Cruz were both among the 16 candidates running against Trump in the Republican presidential primary. And Christie noted that in September, all the contenders signed a pledge to back the party's eventual nominee, no matter who it is.

"He signed a pledge," said the governor, one of Trump's closest advisers. "It's his job to keep his word ... Our words should matter. That's what disgusts people out in the audience about politicians."

Cruz was Trump's fiercest rival in the primary, winning more delegates than any other GOP candidate other than the celebrity businessman and former Atlantic City casino mogul.

But speaking on the third night of the convention Wednesday, Cruz angered a large portion of the crowd by not endorsing Trump. It was the most obvious example this week of a rift that still exists in the party over Trump's candidacy.

"To those listening, please, don't stay home in November," Cruz said. "If you love our country, and love your children as much as I know you do, stand, and speak, and vote your conscience, vote for candidates up and down the ticket who you trust to defend our freedom and to be faithful to the Constitution."

Christie derided the comments as "cute."

"The crowd was waiting for him to do the right thing," the governor said of Cruz. "I think the performance you saw there is why Ted has so richly deserved the reputation he's developed."

A string of other forms 2016 Republican candidates have not backed Trump despite signing the pledge, including Jeb Bush, Carly Fiorina, and John Kasich.

Christie noted they "are not in the room tonight."

"The fact is: He came into this room today and then did not keep his word," the governor said.

Wednesday at the 2016 RNC 35 Gallery: Wednesday at the 2016 RNC

Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01. Find NJ.com Politics on Facebook.