WASHINGTON – The death of Elie Wiesel weighed heavy on the White House on Saturday night, as US President Barack Obama mourned the passing of “one of the great moral voices of our time, and in many ways, the conscience of the world.“Tonight, Michelle and I join people across the United States, Israel and around the globe in mourning the loss and celebrating the life of a truly remarkable human being,” Obama said in a statement issued by the White House, referring to Wiesel as a “living memorial” and a “dear friend.”Obama visited the Buchenwald concentration camp near Weimar with Wiesel in 2009 – the beginning of a long relationship, grounded in their shared commitment to the State of Israel, the president said.“He raised his voice, not just against anti-Semitism, but against hatred, bigotry and intolerance in all its forms,” Obama said. “He implored each of us, as nations and as human beings, to do the same, to see ourselves in each other and to make real that pledge of ‘Never again.’” In New York, United Nations Secretary-General Ban Ki-moon said Wiesel was “a powerful voice” for Holocaust remembrance.“Elie Wiesel turned the nightmare of his youth into a lifelong campaign for global equality and peace,” Ban said in the statement delivered by his spokesman.He noted that Wiesel served as a UN Messenger of Peace since 1998 and was a regular presence at the UN, including at the first-ever International Day of Commemoration in memory of the victims of the Holocaust in 2006.“The United Nations is grateful for Mr. Wiesel’s contributions and remains strongly committed to Holocaust remembrance and the wider struggle for human rights for all,” Ban added. Jewish groups across the United States were mourning Wiesel on Sunday.“Wiesel’s life was an inspiring, indeed towering, example of an individual’s willpower to overcome the worst of human evil, keep alive the memory of six million murdered Jews, and stand guard throughout against the dangers of extremism, indifference and historical amnesia,” American Jewish Committee CEO David Harris said.“Elie Wiesel believed that being Jewish means not necessarily seeking to make the world more Jewish, but rather more human,” Harris said. “That is the goal animating our people, through good times and bad, from the very beginning of this remarkable historical journey to the present day.”The Anti-Defamation League called him “a courageous crusader against forces of hatred and intolerance and a voice of conscience who repeatedly reminded the world of the moral imperative to prevent mass genocide from happening again.”Both the ADL and the AJC interacted regularly with Wiesel after he moved to the United States in 1956.The International March of the Living educational organization, which also worked with Wiesel, said it considers him a “mentor, conscience and inspiration.“We will miss his passion, commitment and dedication to our mission of educating hundreds of thousands of young people and their families around the world on the atrocities of the Holocaust,” March of the Living Chairman Shmuel Rosenman and President Phyllis Greenberg Heideman wrote.Ronald Lauder, president of the World Jewish Congress, added that the Jewish world owes Wiesel “an enormous debt of gratitude” and said he was “undoubtedly one of the great Jewish teachers and thinkers of the past 100 years. “His passing leaves a void that will be impossible to fill. At the same time, his writings will live on,” Lauder said.Other condolence and tribute statements came from Chabad, the Simon Wiesenthal Center, the European Jewish Congress and many others.