According to a hadith of the Prophet ﷺ “He who has hair should honor it.” narrated by Abu Dawoud. Other hadiths confirm it, and some of them authenticated it. The ways of honoring ones hair are many, and it is for men and women, everything which he likes, like combing, applying oil, dyeing it to hide the white hair.
The scholars have spoken on the topic regarding dyeing the hair black, and many of them have prohibited it, but their evidence is only related to men or in the case of deception for an old woman who wants to appear young so that she may appear attractive for marriage. As for the married woman who lets her husband know, then their is no harm in dyeing her hair to what pleases her and her husband, in fact Ibn Al Jawzi allowed it for men, and what was stated about prohibition it was based on temptation and lack of obedience which the Sheikh should improve on in preparation for meeting his Lord.
Shamsudeen Abu Abdullah Muhammad bin Muflih Al Maqdisi Al Hanbali, who died in 762 AH and was a student of ibn Taymiyah, in the book of [Al-Aadab As-Shari’yyah] said:
It is sunnah to cover the white hair of old age, and there is the hadith from the two books sahih, “Jews and Christians do not dye [their beards], so act differently from them.” It is preferred to use henna to conceal it like what the Prophet ﷺ used to do as narrated by Ahmad and Ibn Majah with sound chains. This is also a habit of Abu Bakr and Umar. Dyeing it black is disliked according to the text of Ahmad which he said: It is disliked to use black dye? he said: Yes By Allah, due to the saying of the Prophet ﷺ on the authority of the father of Abu Bakr: “and avoid black” narrated by Muslim.
The reason behind this- as some have explained- is that the old man if he dyes his hair black he would be seen as a laughing stock. Though Ishaaq bin Rahawaih gave an exemption to woman that she may adorn herself for her husband.
Dying with black color is also not disliked for war. The Shafi’s on the other hand, decided that it is preferred that the old men and women should dye their hair with yellow, or red, and that the black is forbidden according to the most correct opinion from them.
Part of the hadith that prohibited using black dye, beside the father of Abu Bakr’s hadith is the Prophet’s saying that: “Some people will dye their hair black like the breasts of pigeons at the end of time, but they will not even smell the fragrance of Paradise.” Narrated by Abu Dawoud and An-Nisai with a sound chain of narrators.