It is narrated from Sayyiduna Abdullah (may Allah be pleased with him), he says: I went to the Noble Prophet (peace and blessings be upon him) and he had a fever. I said to him: O Messenger of Allah! Indeed, you have a very severe fever, what is the reason for this? He (peace and blessings be upon him) said: Yes, indeed I have as much fever as two of you among men. I said: Then is the reward for you also doubled? He (peace and blessings be upon him) said: Yes, by the One in Whose hand is my soul! Whatever pain afflicts a Muslim living on the face of the earth, whether it is illness or any other pain, Allah Almighty wipes out his sins thereby, just as a tree sheds its leaves.

It is narrated from Sayyiduna Asad bin Kurz (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: The sins of a sick person fall away just as the leaves of a tree fall.

Sayyiduna Muawiyah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: Whatever causes pain to a believer’s body, Allah the Exalted makes it an expiation for his sins.

Abu Ash’ath San’ani says: I was going towards the mosque of Damascus in the early morning or at noon, when I met Sayyiduna Shaddad bin Aws (may Allah be pleased with him), and Sayyiduna Sanabahi (may Allah be pleased with him) was with him. I said: May Allah have mercy on you, where are you going? They said: We are going to visit a sick brother. So I also went along with them until they reached that brother and said: How did you start your morning? He said: I started my morning with blessings. Then Sayyiduna Shaddad (may Allah be pleased with him) said: Rejoice in the forgiveness of sins and the erasure of faults, for I heard the Messenger of Allah (peace and blessings be upon him) say that indeed Allah Almighty said: When I test any of My believing servants and he praises Me in this trial, then he rises from his bed as free from sins as the day his mother gave birth to him. Then Allah Almighty further says: I have confined My servant and tested him, so O angels! You continue to record all the deeds for him that you used to record when he was healthy.

Narrated by Sayyida Aisha (may Allah be pleased with her), she says: I have seen the Messenger of Allah (peace and blessings be upon him) in the most severe pain.

Muhammad bin Khalid narrates from his grandfather, who had the honor of companionship, he says: He set out to visit one of his brothers, then he also found out that he was ill, so he went to him and said: I have come to visit you, to look after you, and to give you glad tidings. He said: How did you combine all these things? I said: I set out to visit you, then I also received news of your illness, thus this coming also became a means of tending to you, and I give you glad tidings through this hadith which I myself heard from the Messenger of Allah, peace and blessings be upon him. He, peace and blessings be upon him, said: When Allah Almighty decides for a servant a rank and status with Him which the servant cannot reach by his own deeds, then Allah Almighty begins to test him through his body, or his wealth, or his children, then Allah Almighty also grants him the ability to be patient, until He makes him reach that station which has already been decided for him with Him.

Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates that a man asked the Messenger of Allah (peace and blessings be upon him): What do you say about the illnesses that befall us? The Messenger of Allah (peace and blessings be upon him) said: They become an expiation for sins. My father said: Even if the illness is minor? The Messenger of Allah (peace and blessings be upon him) said: Even if it is a thorn or something greater than that. Upon hearing this, my father supplicated against himself that fever should not leave him until his death, but that the fever should not prevent him from Hajj, Umrah, striving in the way of Allah, or performing obligatory prayers in congregation. After that, whoever touched my father felt the heat of the fever, until he passed away.