Speaking during a visit to Rome's main synagogue on Sunday, he said: "Violence of man against man is in contradiction to every religion that merits the name, in particular the three monotheistic religions.
"Every human being, as a creature of God, is our brother regardless of his origins or religious belief."
The pontiff also used the visit to reject any form anti-Semitism and called for "maximum vigilance" and early intervention to prevent another Holocaust.
He then joined a standing ovation for a number of Holocaust survivors who were present.
The Catholic Church has previously faced criticism for the way it handled the Holocaust.
Some have suggested Pope Pius XII, the Second World War-era pope failed to do enough to protect Jews from Nazi Germany.
The Vatican has long maintained that Pius used behind-the-scenes diplomacy in a bid to save Jewish lives.
In his speech, Pope Francis made no mention of Pius.