When we were on a journey with the Prophet the people complained to him of thirst, so he dismounted and called for so and so (whose name was mentioned by Abu Raja' but forgotten by `Auf) and for `Ali and told them to go and look for water. They went off and met a woman riding with a leather water-bag, or a water-skin on either side of her, so they brought her to the Prophet and asked her to dismount from her camel. The Prophet called for a vessel and poured water into it from the mouths of the skins, after which proclamation was made among the people to draw water, and they did so. Then we forty thirsty men drank till we had had enough, and we filled every skin and small vessel which we had. I swear by God that water was taken from the skin, but it seemed to us to be fuller than it was when he began. (Bukhari and Muslim.)