He said at the CNN Democratic presidential debate on Sunday that just because he doesn't talk about Judaism frequently doesn't mean he's disowning that part of his identity.
"I am very proud to be Jewish. Being Jewish is so much of what I am," Sanders said.
"Look, my father's family was wiped out by Hitler in the Holocaust," he continued. "I know about what crazy and radical and extremist politics mean. I learned that lesson as a tiny, tiny child when my mother would take me shopping and we would see people working in stores who had numbers on their arms because they were in Hitler's concentration camp. I am very proud of being Jewish and that's an essential part of who I am as a human being."
Sanders told The Washington Post in January that he is not involved in organized religion. However, he said he believes in God, which to him "means that all of us are connected, all of life is connected, and that we are all tied together."
At the debate, Sanders told a questioner from the audience that he believes God is relevant, particularly the idea of doing unto others what you would have them do unto you.
"I believe morally and ethically that we do not have a right to turn our backs on children in Flint, Michigan, who are being poisoned or veterans who are sleeping out on the street," Sanders said.