Ibn Umar used to dye his beard with yellow colour so much so that his clothes were filled (dyed) with yellowness. He was asked: Why do you dye with yellow colour? He replied: I saw the Messenger of Allah ﷺ dyeing with yellow colour, and nothing was dearer to him than it. He would dye all his clothes with it, even his turban.  

إِنِّي رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَصْبُغُ بِهَا وَلَمْ يَكُنْ شَىْءٌ أَحَبَّ إِلَيْهِ مِنْهَا وَقَدْ كَانَ يَصْبُغُ بِهَا ثِيَابَهُ كُلَّهَا حَتَّى عِمَامَتَهُ