Asma' bint Abi Bakr · The Book of Adornment

"I saw Ibn 'Umar dyeing his beard yellow with Khaluq and I said: 'O Abu 'Abdur-Rahman, are you dyeing your beard yellow with Khaluq?' He said: 'I saw the Messenger of Allah dyeing his beard yellow with it, and there was no other kind of dye that was dearer to him than this. He used to dye all of his clothes with it, even his 'Imamah (turban).'"

The Messenger of Allah said: "The Jews and the Christians do not dye their hair, so be different from them."