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."  

أَنَّ النَّبِيَّ ﷺ دَخَلَ عَلَى أَعْرَابِيٍّ يَعُودُهُ قَالَ وَكَانَ النَّبِيُّ ﷺ إِذَا دَخَلَ عَلَى مَرِيضٍ يَعُودُهُ فَقَالَ لَهُ لاَ بَأْسَ طَهُورٌ إِنْ شَاءَ اللَّهُ قَالَ قُلْتَ طَهُورٌ كَلاَّ بَلْ هِيَ حُمَّى تَفُورُ أَوْ تَثُورُ عَلَى شَيْخٍ كَبِيرٍ تُزِيرُهُ الْقُبُورَ فَقَالَ النَّبِيُّ ﷺ فَنَعَمْ إِذًا