Ruling on fasting the thirteenth of Dhu al-Hijjah with the intention of the white days

Question: A. A. H. from Buraydah says in his question: My mother, may Allah guide her, fasts the three white days of every month. Naturally, the thirteenth of the month of Dhu al-Hijjah coincides with the third day of Tashreeq. Should she fast it? Or should she be content with fasting only the fourteenth and fifteenth of the month of Dhu al-Hijjah?

Answer: It is not permissible for your mother, nor for anyone else, to fast the thirteenth of Dhu al-Hijjah; because the Prophet (peace and blessings be upon him) forbade fasting the days of Tashreeq, and he said: .
Except for one who is unable to provide the sacrificial animal for Tamattu' or Qiran; in that case, there is no blame on him for fasting them; as al-Bukhari (may Allah have mercy on him) narrated in his Sahih from Aisha and Ibn Umar (may Allah be pleased with them both) that they said: "No permission was given to fast the days of Tashreeq except for one who does not find the sacrificial animal."
She may fast the fourteenth and fifteenth, and if she wishes to fast the sixteenth or another day from the month of Dhu al-Hijjah until she completes three days, that is better; because the Prophet (peace and blessings be upon him) advised a group of the Companions (may Allah be pleased with them) to fast three days of every month, whether they coincide with the white days or not, but if the Muslim fasts them on the white days, it is better. And success is from Allah.