Here is a photo that you can find on the web showing Bernie Sanders, John Lewis and Martin Luther King, Jr.
There are numerous other well-known civil rights advocates in this picture.
I found the unretouched image on the web by googling the strings "bernie sanders mlk photo" and "john lewis mlk photo".
You should find it and others like it for yourself just so you know I am not doing a photoshop job.
John Lewis stated in public on February 11, 2016, when the CBC PAC endorsed Hillary Clinton that
“I never saw him. I never met him, I chaired the Student Nonviolent Coordinating Committee for three years from 1963 to 1966. I was involved in the sit-ins, the Freedom Rides, the March on Washington, the march from Selma to Montgomery and directed the voter education project for six years. I met Hillary Clinton, I met President Clinton.”
The picture shows that John Lewis is incorrect.
If John Lewis is as honest as he appears to be, he needs to make a public apology to Senator Sanders.