While speaking at an African-American church on Sunday, Donald Trump's daughter-in-law forgot a quote about insanity that she had planned to use to insult Democratic nominee Hillary Clinton.

On Sunday, historically black church Antioch Road to Glory International Ministries in Charlotte held a "Day of Endorsement" for the Republican nominee, which was attended by The Apprentice star Omarosa Manigault and daughter-in-law Lara Trump.

Eric Trump's senior assistant, Lynne Patton, and Lara Trump spoke to CNN host Fredricka Whitfield from the church on Sunday following the endorsement ceremony.

Lara Trump explained that her father-in-law had "100 percent" support from members of Antioch Road Church.

Whitfield noted that the church's Facebook page had compared Hillary Clinton to "an abusive ex, one that you already know left you broken and wounded."

Lara Trump tried to drive the point home.

"I had nothing to do with the Facebook page but what I'll tell you is that there's a famous quote that says," she explained before pausing. "Wait, I forgot my quote!"

Patton reminded her that she meant to repeat a quote often attributed to Albert Einstein: "The definition of insanity is doing the same thing over and over and expecting different results."

"What we have is eight years of the same result," she remarked proudly. "You have with Hillary Clinton the same thing you got with Barack Obama."