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When Khizr Khan spoke at the Democratic National Convention Thursday night, few could have predicted his emotional rebuke of Donald Trump would still be driving headlines days later.

But that's exactly what has happened.

The father of a fallen Muslim U.S. Army captain told NBC's "Meet the Press" Sunday that he didn't expect his speech to have such an impact.

"I was surprised myself," Khan said. "I spoke from the heart."

Related: GOP Reacts to Donald Trump's Controversial Remarks on Khan Family

He continued to express his concerns about the Republican nominee, saying, "We have a candidate without a moral compass, without empathy for its citizens."

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Over the weekend, Trump questioned why Khan's wife, Ghazala Khan, did not speak alongside her husband at the convention. "Maybe she wasn't allowed to have anything to say," he said in part.

Responding to these remarks, Khan claimed Trump was showing "disrespect" toward his wife.

"We don't take these values lightly," he continued. "We are testament to the goodness of this country. We experience the goodness of this country every day."

The Trump campaign released a statement Saturday clarifying Mr. Trump's comments, saying he believes Captain Humayun Khan, is "a hero to our country."

Khizr Khan expressed his appreciation for Trump's clarification, but added "it sounds so disingenuous because of his policies, because of his rhetoric of hatred, of derision, of dividing us. And that is why I implored him to read the Constitution."

Also on Sunday morning, wife and mother Ghazala Khan penned an op-ed for the Washington Post where she responded to Trump's criticism.

Donald Trump has asked why I did not speak at the Democratic convention," she wrote. "He said he would like to hear from me. Here is my answer to Donald Trump: Because without saying a thing, all the world, all America, felt my pain. I am a Gold Star mother. Whoever saw me felt me in their heart."

In a separate interview on "Meet the Press," Trump campaign Chairman Paul Manafort dismissed criticism of his candidate as attacking the Khan family as part of "the Clinton narrative."

He further explained, "Mr. Trump, of course, feels sorry for what the Khan family has gone through, just, frankly, as he felt sorry for the victims that spoke before the Republican Convention who lost loved ones from illegal immigrant criminals coming in and being able to travel the country freely."

The issue voters should focus on, he said, "is protecting the American homeland from national security risks and terrorists."

Pressed on if this latest incident should call into question Trump's temperament, Manafort was, again, dismissive.

"This is not a temperament issue. The Clinton campaign needs to try to make it into a temperament issue for one reason, because they know that over 70 percent of the American people don't believe a thing she says."