Musnad Ahmad 32:822

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, and Hajjaj narrated to us, he said: Shu'bah narrated to me, he said: I heard Qatadah narrating from Anas ibn Malik, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There are three things, whoever possesses them will find the sweetness of faith: that a person loves another, not loving him except for the sake of Allah; and that Allah and His Messenger are more beloved to him than anything else; and that being cast into the Fire is more beloved to him than returning to disbelief after Allah has saved him from it."