It is narrated from Sayyiduna Abu Sa'id (may Allah be pleased with him) that a group of the Ansari Companions went on a journey. On the way they camped near an Arab tribe and asked them for food, but they refused to host them. The chief of the tribe was bitten by a snake. They tried everything, but nothing brought relief. One person said: Go to the group that has stopped near you; perhaps they have some remedy for it. So they said: O group, our chief has been bitten by a snake, and we have tried everything, but he is not recovering. Do you have any remedy or solution for it? One of the Companions said: Yes, I know how to perform ruqyah, but we asked you for food and you refused to host us, so now I will not perform ruqyah until you give me something in return. So they agreed with the Companions on a flock of goats. That Companion went and began performing ruqyah over him, reciting Surah al-Fatihah. After a short while he became completely well, as if he had been released from ropes, and he began walking as though nothing ailed him. So they paid the compensation as promised. People said: Divide it. The Companion who had performed ruqyah said: Wait! Let us go to the Messenger of Allah (peace and blessings be upon him) and ask about the matter, then (do) whatever he commands. So in the morning they came to the Messenger of Allah (peace and blessings be upon him) and related the story. The Messenger of Allah (peace and blessings be upon him) smiled and said: "How did you know that it is a ruqyah?" Then he said: "You did right. Divide it, and keep a share for me with you as well."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإجارة / 11677