Musnad Abu Ya'la al-Mawsili 106:2

Abu Bakr ibn Abi Shaybah narrated to us, Abu Usamah narrated to us, from Zakariya, from Abu Ishaq, from al-Bara’ who said: We descended with the Prophet, peace and blessings of Allah be upon him, at al-Hudaybiyah. We found that the first of the people had drunk its water. The Prophet, peace and blessings of Allah be upon him, sat at the well and called for a bucket of it. He took some of it into his mouth, then spat it into it, and called upon Allah the Exalted. Its water increased until the people were quenched from it.