Sahih Muslim | Book 24 | Hadith Number 5243

Narrated by Jabir
Jabir reported that when Abu Qubafa (father of Abu Bakr) came in the Victory or on the Day of Victory (to the Holy Prophet to pledge his allegiance to him) his head and his beard were white like hyssop. He (the Holy Prophet) commanded or the women were commanded by him that they should change this with something (that the colour of his hair should be changed).