Sunan At-Tirmidhi
Hadith #1178
Hammad bin Yazid said:""I said to Abu Ayyub: 'Do you know of anyone who said that: ""Your case is up to you?"" counts as three besides Al-Hasan?' He said: ""No, not besides Al-Hasan.' Then he said: 'O Allah forgive me - except for what has been narrated to me by Qatadah, from Kathir the freed slave of Banu Samurah, from Abu Salamah, from Abu Hurairah, that the Prophet said: ""Three.'""Abu Ayyub said: 'So I met Kathir the freed slave of Banu Samurah and asked him about it, but he was not aware of it. So I returned to Qatadah and informed him about that and he said: ""He forgot