Musnad Abu Ya'la al-Mawsili 45:11

Al-Hasan ibn Abi al-Rabi' al-Jurjani narrated to us, 'Abd al-Samad ibn 'Abd al-Warith narrated to us, my father narrated to me, from 'Ali ibn Zayd, from Anas ibn Malik, who said: The sky rained hail. Abu Talha said to us, while we were young boys, "Hand me some of that hail, O Anas." He began to eat it while he was fasting. I said, "Are you not fasting?" He said, "Yes, but this is neither food nor drink; it is merely a blessing from the sky with which we purify our stomachs." Anas said: So I came to the Prophet, peace and blessings of Allah be upon him, and informed him. He said, "Take from your uncle."