Musnad Abu Ya'la al-Mawsili 116:38

Ahmad narrated to us, Hajjaj ibn Muhammad narrated to us, Shu'bah narrated to me, from Qatadah, from Ikrimah, who said: When this verse was revealed: "Indeed, We have given you a clear conquest, that Allah may forgive for you what preceded of your sin and what will follow," the companions of the Messenger of Allah (peace be upon him) said: "Congratulations and pleasantness to you, O Messenger of Allah! But what is for us?" He said: Then this verse was revealed: "That He may admit the believing men and the believing women to gardens beneath which rivers flow." Shu'bah said: Qatadah used to mention this hadith in his stories from Anas, saying: This verse was revealed when the Messenger of Allah (peace be upon him) returned from al-Hudaybiyyah: "Indeed, We have given you a clear conquest, that Allah may forgive for you..." He said: Then he would say: The companions of the Messenger of Allah (peace be upon him) said: "Congratulations to you, O Messenger of Allah." He (Shu'bah) said: I thought that it was all from Anas. He said: So I came to Kufa and narrated it from Qatadah, from Anas. Then I returned and met Qatadah in Wasit, and behold, he was saying the first part of it from Anas and the last part of it from Ikrimah. He said: So I came to them in Kufa and informed them of that.