Musnad Abu Ya'la al-Mawsili 115:364

Ubayd Allah narrated to us, Yazid bin Zuray' narrated to us, from Sa'id, from Qatadah, from Anas, who said: This verse was revealed to the Prophet, may Allah bless him and grant him peace, upon his return from al-Hudaybiyyah. It was revealed while he and his companions were overcome with sadness, and they were prevented from their rites, so they slaughtered their sacrificial animals at al-Hudaybiyyah. When this verse was revealed, he said to his companions: "A verse has been revealed to me that is more beloved to me than the entire world." When the Prophet of Allah, may Allah bless him and grant him peace, recited it, a man from the people said: "Congratulations and may it be wholesome, O Prophet of Allah. Allah has clarified to us what He will do with you, so what will He do with us?" Then Allah revealed after it: "That He may admit the believing men and the believing women to gardens beneath which rivers flow" (Surah al-Fath).