The Book of Fasting
13/40. Chapter:
The virtue of Lailat Al-Qadr and the Exhortation to seek it; When it is and the most likely times to seek it
Sahih Muslim
وَحَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، أَخْبَرَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، ح وَحَدَّثَنَا عَبْدُ اللَّهِ، بْنُ عَبْدِ الرَّحْمَنِ الدَّارِمِيُّ أَخْبَرَنَا أَبُو الْمُغِيرَةِ، حَدَّثَنَا الأَوْزَاعِيُّ، كِلاَهُمَا عَنْ يَحْيَى بْنِ أَبِي، كَثِيرٍ بِهَذَا الإِسْنَادِ . نَحْوَهُ وَفِي حَدِيثِهِمَا رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم حِينَ انْصَرَفَ وَعَلَى جَبْهَتِهِ وَأَرْنَبَتِهِ أَثَرُ الطِّينِ .
This hadith has been reported on the authority of Yahya b. Abu Kathir with the same chain of transmitters (with a slight variation of these words): I saw the Messenger of Allah (ﷺ) after he had completed (the prayer) and there was a trace of clay on his forehead and tip (of the nose).
Reference : Sahih Muslim 1167eIn-book reference : Book 13, Hadith 279USC-MSA web (English) reference : Book 6, Hadith 2629