Musnad Ahmad 32:1936

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, and Hajjaj narrated to us, he said: Shu'bah narrated to me, he said: I heard Qatadah narrating from Anas ibn Malik: "The Prophet, peace and blessings of Allah be upon him, was brought a man who had drunk wine, so he lashed him about forty [times], and Abu Bakr did the same." "Then when it was the time of Umar, he consulted the people. Abd al-Rahman ibn Awf said: 'The lightest of the prescribed punishments is eighty [lashes].' So Umar ordered it." And Hajjaj said: "Eighty, and Umar ordered it."