كتاب الصيام
13  
The Book of Fasting
(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
(40)
باب فَضْلِ لَيْلَةِ الْقَدْرِ وَالْحَثِّ عَلَى طَلَبِهَا وَبَيَانِ مَحَلِّهَا وَأَرْجَى أَوْقَاتِ طَلَبِهَا
Sahih Muslim 1167 e

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).
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 ‏.‏
Reference : Sahih Muslim 1167e
In-book reference : Book 13, Hadith 279
USC-MSA web (English) reference : Book 6, Hadith 2629
  (deprecated numbering scheme)