Former President Biden mourned Pope Francis in an op-ed, arguing that it is up to his admirers to carry on his legacy of service and compassion to the world.

Former President Joe Biden said Pope Francis was “unlike any who came before him” as he paid tribute to “the People’s Pope” on Monday. Biden, the second Roman Catholic U.S. president, described the late pontiff as “one of the most consequential leaders of our time” as world leaders reacted to the news of the 88-year-old’s death.