Sunan an-Nasa'i 5068
It was narrated from 'Amr bin Shu'aib, from his father, from his grandfather, that:
The Messenger of Allah [SAW] forbade plucking gray hairs.
أَخْبَرَنَا قُتَيْبَةُ، عَنْ عَبْدِ الْعَزِيزِ، عَنْ عُمَارَةَ بْنِ غَزِيَّةَ، عَنْ عَمْرِو بْنِ شُعَيْبٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنْ نَتْفِ الشَّيْبِ ‏.‏