Musnad Ahmad 435:42

'Abd al-Razzaq narrated to us, from Sufyan, from 'Asim ibn Abi al-Najud, from Dhakwan, from Mu'awiyah ibn Abi Sufyan, from the Prophet, may Allah bless him and grant him peace, who said regarding the drinker of wine: "If he drinks wine, then flog him. Then if he drinks, then flog him. Then if he drinks a third time, then flog him. Then if he drinks a fourth time, then strike his neck."