Musnad Ahmad 658:96

Waki’ narrated to us, Isra’il narrated to us, from Abu Ishaq, from Al-Bara’ who said: We arrived at Al-Hudaybiyyah, and it was a well that had been drained, and we were fourteen hundred. He said: "He drew a bucket from it, and the Prophet, peace and blessings of Allah be upon him, rinsed his mouth with it, then spat it into it, and supplicated." He said: So we drank our fill and watered our animals. And Waki’ said: "Fourteen hundred."