Al-Kāfi - Volume 3 > Causes of Death and that Believing People May Die by any Manner of Dying
Hadith #7

7ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ مُوسَى بْنِ الْحَسَنِ عَنِ الْهَيْثَمِ بْنِ أَبِي مَسْرُوقٍ عَنْ شَيْخٍ مِنْ أَصْحَابِنَا يُكَنَّى بِأَبِي عَبْدِ الله عَنْ رَجُلٍ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ قَالَ رَسُولُ الله (صلّى اللهُ عَلَيْهِ وَآلِه) الْحُمَّى رَائِدُ الْمَوْتِ وَسِجْنُ الله تَعَالَى فِي أَرْضِهِ وَفَوْرُهَا مِنْ جَهَنَّمَ وَهِيَ حَظُّ كُلِّ مُؤْمِنٍ مِنَ النَّارِ.

7. Muhammad ibn Yahya has narrated from Musa ibn al-FIassan from al-Haytham ibn al-Masruq from a shaykh of our people called abu ‘Abd Allah from a man who has said the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said that the Messenger of Allah has said, ‘Fever is a harbinger of death and a prison of Allah on earth. Its heat is from hell and that is the share of a believing person (instead) of hellfire.’”