The Mississippi Civil rights Museum in Jackson will open Saturday.
"President Trump's attendance and his hurtful policies are an insult to the people portrayed in this civil rights museum," the lawmakers said. "The struggles represented in this museum exemplify the truth of what really happened in Mississippi."
"Trump's disparaging comments about women, the disabled, immigrants, and National Football League players disrespect the efforts of Fannie Lou Hamer, Aaron Henry, Medgar Evers, Robert Clark, James Chaney, Andrew Goodman, Michael Schwerner, and countless others who have given their all for Mississippi to be a better place."
Lewis has played key roles in the civil rights movement since the 1960s. He has represented Georgia's 5th District in the House since 1987.
Although they won't be there, Lewis and Thompson encouraged all Americans to visit the museum -- "after President Trump departs."
"The president hopes others will join him in recognizing that the movement was about removing barriers and unifying Americans of all backgrounds," Sanders said.
Members of the Congressional Black Caucus slammed the White House's criticism.
"It's laughable that the White House is criticizing Rep. John Lewis and Rep. Bennie Thompson for not attending the opening of a civil rights museum that honors the sacrifice of ... John Lewis, Bennie Thompson & many others," CBC Chairman Rep. Cedric Richmond said.
The museum will open at 11 a.m. Saturday and will feature speakers including Myrlie Evers, the widow of slain civil rights leader Medgar Evers, and Mississippi Gov. Phil Bryant.