Musnad Ahmad 32:1970

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, and Hajjaj said: Shu‘bah narrated to me, he said: I heard Qatadah narrating from Anas ibn Malik, that he said regarding this verse: {Indeed, We have given you a clear conquest} [Al-Fath: 1]: "Al-Hudaybiyyah."