Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Abu Dharr (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: "The best thing with which the whiteness of hair can be changed is henna leaves and katam."

It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Change the whiteness of your hair and do not imitate the Jews and Christians."

Sayyiduna Uqbah bin Abd (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings of Allah be upon him) used to command changing the whiteness of the hair, so that there would be opposition to the non-Arabs.

Sayyiduna Abu Umamah (may Allah be pleased with him) says: The Messenger of Allah (peace and blessings of Allah be upon him) came to some Ansaris with white beards and said: "O group of Ansaris! (Color your white hair) red or yellow and oppose the People of the Book." They said: O Messenger of Allah! Indeed, the People of the Book trim their beards and grow their mustaches. The Messenger of Allah (peace and blessings of Allah be upon him) said: "You grow your beards and trim your mustaches and oppose the People of the Book." They said: O Messenger of Allah! Indeed, the People of the Book wear leather socks and do not wear shoes. He (peace and blessings of Allah be upon him) said: "You wear shoes as well as socks and oppose the People of the Book."