Musannaf Ibn Abi Shayba 36:195

Yazid ibn Harun narrated to us, he said: Hammad ibn Salamah informed us, from Asim ibn Abi al-Najud, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Indeed, Allah, Blessed and Exalted is He, looked upon the people of Badr and said: 'Do what you wish, for I have forgiven you.'"