Musnad Abu Ya'la al-Mawsili 42:68

'Abd al-A'la narrated to us, Hammad bin Salamah narrated to us, from Abu al-Tayyah, from Abu al-Wadak, from Abu Sa'id al-Khudri: That the Messenger of Allah (ﷺ) was brought a drinker. The Messenger of Allah (ﷺ) said to him, "What did you drink?" He said, "I did not drink wine; they were only some raisins and dates that I put in a gourd for myself." So the Messenger of Allah (ﷺ) forbade mixing raisins and dates.