(CNN) More than two decades after "Schindler's List" first debuted, Steven Spielberg's award-winning film about the horrors of the Holocaust is returning to theaters.

"I think there is more at stake today than even back then," Spielberg said in an extended interview with NBC published Wednesday. "When collective hate organizes and gets industrialized, then genocide follows. We have to take it more seriously today than I think we have had to take it in a generation." Spielberg's comments come in the wake of the October massacre at the Tree of Life Synagogue in Pittsburgh in which 11 people were fatally shot. "Schindler's List," which premiered in 1993, tells the story of Oskar Schindler, a German businessman who helped save the lives of 1,200 Jews during the Holocaust by employing them in his factories. The film won seven Academy Awards, including best picture and the Oscar for best director. Read More "I couldn't imagine based on the story that we told that an audience would tolerate just the amount of violence, human against human. Or inhuman against human," Spielberg told NBC. Depicting the brutality of the Holocaust took a toll on Spielberg and the cast of "Schindler's List." "I think everybody felt that we were memorializing something," Spielberg said. "I've only had this experience twice, one was shooting 'Schindler's List,' and the second time, it was very reverential, was shooting 'Lincoln.' The two times that I think the entire company came together to pay their respects." To mark the 25th anniversary of the film, "Schindler's List" will re-release in theaters across the US and Canada for a limited run on December 7. "I don't think I'll ever do anything as important," Spielberg said. "So this, for me, is something that I will always be proudest of."