Abu Salama bin 'Abdur Rahman أبو سلمة بن عبد الرحمن بن عوف · Combing the Hair (Kitab Al-Tarajjul)

Do not pluck out grey hair. If any believer grows a grey hair in Islam, he will have light on the Day of Resurrection. (This is Sufyan's version). Yahya's version says: Allah will record on his behalf a good deed for it, and will blot out a sin for it.