Musnad Ahmad 32:912

Waki’ narrated to us, Hisham narrated to us, from Qatadah, from Anas, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) used to punish for [drinking] wine with sandals and palm branches." He said: "Then Abu Bakr struck forty [lashes]. When the time of Umar came and people drew near to the countryside and the villages, he consulted the people regarding that, and it [the drinking of wine] spread among the people. Abd al-Rahman ibn Awf said: 'I see that you should make it like the lightest of the prescribed punishments.' So Umar struck eighty [lashes]."