Sahih al-Bukhari Book 75, Hadith 15
Usama bin Zaid said that while he. Sa`d and Ubai bin Ka`b were with the Prophet (ﷺ) a daughter of the
Prophet sent a message to him, saying. 'My daughter is dying; please come to us." The Prophet (ﷺ) sent
her his greetings and added "It is for Allah what He takes, and what He gives; and everything before
His sight has a limited period. So she should hope for Allah's reward and remain patient." She again
sent a message, beseeching him by Allah, to come. So the Prophet (ﷺ) got up. and so did we (and went
there). The child was placed on his lap while his breath was irregular. Tears flowed from the eyes of
the Prophet. Sa`d said to him, "What is this, O Allah's Messenger (ﷺ)?" He said. "This Is Mercy which Allah
has embedded in the hearts of whomever He wished of His slaves. And Allah does not bestow His
Mercy, except on the merciful among His slaves. (See Hadith No. 373 Vol. 2)
When Allah's Messenger (ﷺ) emigrated to Medina, Abu Bakr and Bilal got a fever. I entered upon them and asked, "O my father! How are you? O Bilal! How are you?" Whenever fever attacked Abu Bakr, he would recite the following poetic verses: 'Everybody is staying alive among his people, yet death is nearer to him than his shoe laces." And whenever the fever deserted Bilal, he would recite (two poetic lines): 'Would that I could stay overnight in a valley wherein I would be surrounded by Idhkhir and Jalil (two kinds of good smelling grass). Would that one day I would drink of the water of Majinna and would that Shama and Tafil (two mountains at Mecca) would appear to me.' Then I came and informed Allah's Messenger (ﷺ) about that, whereupon he said, "O Allah! Make us love Medina as much or more than we love Mecca. O Allah! Make it healthy and bless its Mudd and Sa for us, and take away its fever and put it in Al Juhfa."
The Prophet (ﷺ) went to visit a sick bedouin. Whenever the Prophet (ﷺ) went to a patient, he used to say to him, "Don't worry, if Allah will, it will be expiation (for your sins):" The bedouin said, "You say expiation? No, it is but a fever that is boiling or harassing an old man and will lead him to his grave without his will." The Prophet (ﷺ) said, "Then, yes, it is so."