The Holocaust was a horror and a disgrace to humanity and must never be repeated, Pope Francis wrote in a letter to his friend Rabbi Abraham Skorka of Buenos Aires, Vatican Radio reported on Monday.
The hand-written letter will be read out Monday evening at a concert in Rome entitled "Violins of Hope."
The concert, that commemorates the International Holocaust Remembrance Day, will feature works by Barber, Vivaldi and Beethoven.
In addition, twelve violins that survived the Holocaust will be played together for the first time at the concert. The instruments were discovered and restored by Israeli violin maker Amnon Weinstein.