Sahih Muslim 2783
Iyas reported on the authority of his father:
We went along with Allah's Messenger (ﷺ) to visit a person suffering from fever. When I placed my hand upon him, I said: By Allah, I have never seen, till this day, a person running higher temperature than he. Thereupon Allah's Apostle (ﷺ), turning his face to his companions, said: May I not inform you of a severer temperature than this which these two persons would run on the Day of Resurrection? And they were two hypocrites riding upon the camel turning their back towards (the Muslims).
حَدَّثَنِي عَبَّاسُ بْنُ عَبْدِ الْعَظِيمِ الْعَنْبَرِيُّ، حَدَّثَنَا أَبُو مُحَمَّدٍ النَّضْرُ بْنُ مُحَمَّدِ بْنِ،
 مُوسَى الْيَمَامِيُّ حَدَّثَنَا عِكْرِمَةُ، حَدَّثَنَا إِيَاسٌ، حَدَّثَنِي أَبِي قَالَ، عُدْنَا مَعَ رَسُولِ اللَّهِ صلى
 الله عليه وسلم رَجُلاً مَوْعُوكًا - قَالَ - فَوَضَعْتُ يَدِي عَلَيْهِ فَقُلْتُ وَاللَّهِ مَا رَأَيْتُ كَالْيَوْمِ
 رَجُلاً أَشَدَّ حَرًّا ‏.‏ فَقَالَ نَبِيُّ اللَّهِ صلى الله عليه وسلم ‏
"‏ أَلاَ أُخْبِرُكُمْ بِأَشَدَّ حَرًّا مِنْهُ يَوْمَ
 الْقِيَامَةِ هَذَيْنِكَ الرَّجُلَيْنِ الرَّاكِبَيْنِ الْمُقَفِّيَيْنِ ‏"‏ ‏.‏ لِرَجُلَيْنِ حِينَئِذٍ مِنْ أَصْحَابِهِ ‏.‏