Uthman ibn Affan reported: The Prophet, peace and blessings be upon him, would run his fingers through his beard during ablution.
Al-Tirmidhi said, “According to this, the majority of the people of knowledge among the companions of the Prophet, and those after them, hold the opinion that fingers should be run through the beard. It was said by Al-Shafi’i. Ahmad said if one overlooks running his fingers through the beard, it is still permitted.”
Source: Sunan al-Tirmidhī 31
Grade: Sahih (authentic) according to Al-Tirmidhi
(عَنْ عُثْمَانَ بْنِ عَفَّانَ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يُخَلِّلُ لِحْيَتَهُ (في الوضوء
قال الترمذي بِهَذَا أَكْثَرُ أَهْلِ الْعِلْمِ مِنْ أَصْحَابِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَمَنْ بَعْدَهُمْ رَأَوْا تَخْلِيلَ اللِّحْيَةِ وَبِهِ يَقُولُ الشَّافِعِيُّ وَقَالَ أَحْمَدُ إِنْ سَهَا عَنْ تَخْلِيلِ اللِّحْيَةِ فَهُوَ جَائِزٌ
31 سنن الترمذي كتاب الطهارة باب ما جاء في تخليل اللحية
31 المحدث الترمذي خلاصة حكم المحدث حسن صحيح في سنن الترمذي