Musnad Abu Ya'la al-Mawsili 2:88

Abu Hisham al-Rifa'i narrated to us, Ishaq bin Sulayman narrated to us, Mu'awiyah bin Yahya narrated to us, from al-Zuhri, from Sa'id bin al-Musayyib, from Umar, who said: The Prophet, may Allah bless him and grant him peace, heard a man saying to another man, "Come, let me gamble with you." So he ordered him to give charity.