Musnad Ahmad 30:1343

Yunus ibn Muhammad narrated to us, Hammad ibn Salamah narrated to us, from Abu al-Muhazzam, from Abu Hurairah, who said: Seven mastigures (dhabb) were brought to the Prophet, peace and blessings of Allah be upon him, with dates and ghee upon them. He said: "Eat, for I find them repulsive."