It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that one night he was with the Messenger of Allah (peace and blessings be upon him) on a journey. When dawn was near, the Messenger of Allah (peace and blessings be upon him) halted to camp. All the people fell asleep until the sun began to rise high. The first to wake up was Sayyiduna Abu Bakr (may Allah be pleased with him), and no one would wake the Messenger of Allah (peace and blessings be upon him); rather, he would wake up by himself. Then Sayyiduna Umar (may Allah be pleased with him) got up, sat near the head of the Prophet (peace and blessings be upon him), and began to say the takbir in a loud voice. When the Prophet (peace and blessings be upon him) woke up and saw that the sun was shining, he said: "Move on from here." The Companions moved on from there until the sun became white, then he (peace and blessings be upon him) halted and prayed. Meanwhile, one man did not pray with us, so the Prophet (peace and blessings be upon him) asked: "Why did you not pray?" He said: O Messenger of Allah, I am in a state of major ritual impurity (janabah). He (peace and blessings be upon him) ordered: "Perform dry ablution (tayammum) and pray." And the Messenger of Allah (peace and blessings be upon him) sent me with a few riders to look for water, while we were extremely thirsty. While we were still searching for water, we caught sight of a woman sitting with her legs hanging between two water-skins. We asked her: Where is the water? She said: Oh, where would there be water here! We said: How far is it between your people and the water? She said: A day and a night. The Companions said: Then come with us to the Messenger of Allah (peace and blessings be upon him). She said: To the Messenger of Allah? We did not argue with her at all and brought her to him (peace and blessings be upon him). She repeated the same thing before the Prophet (peace and blessings be upon him), and she also told him that she had orphaned children. the Messenger of Allah (peace and blessings be upon him) had her two water-skins brought down, opened their mouths and put his saliva into them. We, forty thirsty men, drank so much that we were fully quenched, and we filled all our vessels, and we also had that man in the state of janabah take a ritual bath (ghusl). But we did not give water to any animal, and the water-skins began to overflow because of the abundance of water. Then he (peace and blessings be upon him) said to us: "Bring whatever you have!" So we gathered pieces of bread and dates and presented them in a bundle to him (peace and blessings be upon him). The Messenger of Allah (peace and blessings be upon him) said to that woman: "Take this and feed your family, and know that we have not taken anything from your water."
When she came to her people, she said: I met the greatest sorcerer among people, or else he is a prophet as they claim. Then Allah guided that settlement through that woman, so she accepted Islam and they accepted Islam.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1047