Sunan an Nasai
5114
Sahih+2

It was narrated that Simak said:"I heard Jabir bin Samurah being asked about the gray hairs of the Prophet [SAW]. He said: 'If he put oil on his head they could not be seen, but if he did not put oil on his head, they could be seen

SahihAbu Ghuddah
SahihAl-Albani