Sayyidina Thawban (RA) reported that the Prophet (SAW) said, “If one of you is afflicted with fever and fever is a piece of the Fire, then extinguish it with water. Let him get down into a river and face the flow of it and say: 'In the name of Allah, O Allah, cure Your slave and confirm the truth of your Messenger'. After the salah of fajr, and before sunrise. Let him plunge into it three times, for three days. If he is not cured in three days then (do it) for five days. And, if he is not cured in five days then let him do it for seven days. And if he is not cured in seven days then nine days, for it will not exceed nine days, with Allah’s permission.”
[Ahmed 22488]
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