Narrated Ibn 'Abbas:

Allah's Apostle entered upon sick man to pay him a visit, and said to him, "Don't worry, Allah willing, (your sickness will be) an expiation for your sins." The man said, "No, it is but a fever that is boiling within an old man and will send him to his grave." On that, the Prophet ﷺ said, "Then yes, it is so."

حَدَّثَنَا إِسْحَاقُ، حَدَّثَنَا خَالِدُ بْنُ عَبْدِ اللَّهِ، عَنْ خَالِدٍ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ ﷺ دَخَلَ عَلَى رَجُلٍ يَعُودُهُ فَقَالَ " لاَ بَأْسَ طَهُورٌ إِنْ شَاءَ اللَّهُ ". فَقَالَ كَلاَّ بَلْ حُمَّى تَفُورُ عَلَى شَيْخٍ كَبِيرٍ كَيْمَا تُزِيرَهُ الْقُبُورَ. قَالَ النَّبِيُّ ﷺ " فَنَعَمْ إِذًا ".