Musnad Ahmad 32:199

Yahya and Abu Nu'aym narrated to us, they said: Hisham narrated to us, Qatadah narrated to us, and Abu Nu'aym said: From Qatadah, from Anas, who said: "The Prophet, peace and blessings of Allah be upon him, flogged for wine with palm branches and sandals, and Abu Bakr flogged" — Yahya said in his narration: — "forty." When it was the time of Umar and the people drew near to the countryside and the villages, he said to his companions: "What do you see?" Abd al-Rahman said: "Make it like the lightest of the prescribed punishments." So Umar flogged eighty.