Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates: A Muslim asked, "O Messenger of Allah (peace and blessings be upon him)! What do you think about these illnesses that befall us—what benefit do we get from them?" The Prophet (peace and blessings be upon him) said: "They become an expiation (for sins)." He asked, "O Messenger of Allah (peace and blessings be upon him), even if they are minor?" The Prophet (peace and blessings be upon him) said: "Even if it is a prick of a thorn or less than that." The narrator says: That person prayed for himself that he would have fever until his death, but that the fever would not prevent him from Hajj, Umrah, striving in the way of Allah, or congregational prayer. The narrator states: Whoever touched his body would feel its heat, until that person passed away. (Imam Ibn Hibban, may Allah have mercy on him, says:) The female narrator named Zainab is Zainab bint Ka'b bin Malik, and the person who prayed for himself was Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him).