37:89As-Saaffaat

“The Messenger of Allah (ﷺ) entered upon me when I was unwell. He said: ‘Do you intend to perform Hajj this year?’ I said: ‘I am sick, O Messenger of Allah.’ He said: ‘Go for Hajj and say: “I will exit Ihram from the point where I am prevented.’”

“O Muhammad, you are ill. He said: ‘Yes.’ He said: Bismillahi arqika, min kulli shay’in yu’dhika, min sharri kulli nafsin aw ‘aynin aw hasidin. Allahu yashfika, bismillahi arqika (In the Name of Allah I perform Ruqyah for you, from everything that is harming you, from the evil of every soul or envious eye, may Allah heal you. In the Name of Allah I perform Ruqyah for you).

Messenger of Allah, I intend to perform Hajj, but I am ill. Thereupon Allah's Apostle (ﷺ) said: Enter Into the state of Ihram on condition that you would abandon it when Allah would detain you.

When the Prophet (ﷺ) fell ill in his fatal illness, he started saying, "With the highest companion."

Allah's Messenger (ﷺ) entered upon a sick bedouin in whom he went to visit and said to him, "Don't worry, Tahur (i.e., your illness will be a means of cleansing of your sins), if Allah Will." The bedouin said, "Tahur! No, but it is a fever that is burning in the body of an old man and it will make him visit his grave." The Prophet (ﷺ) said, "Then it is so."