Jami` at-Tirmidhi 2086
جامع الترمذي#2086Da'ifحَدَّثَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ أَخْبَرَنَا الْوَلِيدُ بْنُ مُحَمَّدٍ الْمُوَقَّرِيُّ، عَنِ الزُّهْرِيِّ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّمَا مَثَلُ الْمَرِيضِ إِذَا بَرَأَ وَصَحَّ كَالْبَرْدَةِ تَقَعُ مِنَ السَّمَاءِ فِي صَفَائِهَا وَلَوْنِهَا " .
Anas bin Malik narrated that the Messenger of Allah (S.A.W) said:"The parable of the ill when he is cured and becomes healthy is that of hail that falls from the heavens in its purity and its color
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 28:51