Musnad Ahmad 32:1303

Muhammad ibn Bakr narrated to us, Sa’id and ‘Abd al-Wahhab informed us, from Sa’id, from Qatadah, from Anas ibn Malik, who said: When this verse was revealed to the Prophet, may God bless him and grant him peace: "Indeed, We have given you a clear conquest, that God may forgive for you what preceded of your sin and what will follow" [Al-Fath: 1-2], upon his return from Al-Hudaybiyyah, while they were overcome with sadness and distress, and he had slaughtered the sacrificial animals at Al-Hudaybiyyah, he said: "A verse has been revealed to me that is more beloved to me than the entire world." They said: "O Messenger of God, we have known what will be done with you, but what will be done with us?" Then it was revealed: "That He may admit the believing men and the believing women to gardens beneath which rivers flow, to abide therein forever, and remove from them their misdeeds; and that is, in the sight of God, a great attainment" [Al-Fath: 5]. ‘Abd al-Wahhab said in his narration: "And his companions were overcome with sadness and distress." And he said in it: "A speaker said: 'Congratulations and may it be wholesome for you, O Messenger of God; God has made clear what He will do with you.'"