Sunan an-Nasai 19988
In-book no 5252أَخْبَرَنَا يَحْيَى بْنُ حَكِيمٍ، قَالَ حَدَّثَنَا أَبُو قُتَيْبَةَ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ عُبَيْدٍ، قَالَ رَأَيْتُ ابْنَ عُمَرَ يُصَفِّرُ لِحْيَتَهُ فَقُلْتُ لَهُ فِي ذَلِكَ فَقَالَ رَأَيْتُ النَّبِيَّ صلى الله عليه وسلم يُصَفِّرُ لِحْيَتَهُ .
It was narrated that 'Ubaid said: "I saw Ibn 'Umar dyeing his beard yellow and I asked him about that. 'He said: "I saw the Prophet dye his beard yellow."