"We have to stand up. We have to speak up and not try to sweep it under the rug," Lewis said on ABC's "This Week" when asked what can be done about it.
In a meeting with lawmakers last week, Trump reportedly questioned why the U.S. accepted so many immigrants from “shithole” countries such as Haiti, El Salvador and African nations. He suggested the U.S. should instead take in more immigrants from countries like Norway.
Lewis, who along with King was a leader of the civil rights movement in the 1960s, said Sunday it's "impossible" to square Trump's reported vulgar comments with his remarks in support of King's legacy.
"There's not any way you can do that. It's unreal. It's unbelievable. It makes me sad. It make me cry," Lewis said.
Lewis reiterated that he plans to skip Trump's State of the Union address later this month.
Lewis and Trump have traded barbs before. Lewis drew the president’s ire last January, before Trump officially took office, after saying he didn't consider him to be a “legitimate president."
Trump said on Twitter the congressman should “spend more time on fixing and helping his district, which is in horrible shape and falling apart (not to mention crime infested).”
Lewis was one of 58 House Democrats who last month voted in favor of beginning impeachment proceedings against Trump. The measure overwhelmingly failed in the GOP-led House.