The virtue of the last ten days of Dhu al-Hijjah and fasting in them

Question:
Umm Salim has this question. She asks, Shaykh, saying: What is prescribed when the last ten days enter? Is fasting in them obligatory? And what are the righteous deeds in them?

Answer:
The last ten days—the first ten days of Dhu al-Hijjah—have a great virtue. Allah (Exalted and Majestic is He) says, “And [remember] Allah during the counted days,” and these are the ten days of Dhu al-Hijjah. And regarding these ten days, the Prophet (peace and blessings be upon him) said, So the deeds in them are multiplied, and there is a great virtue in them. One should occupy them with the remembrance of Allah and with fasting; he fasts them and increases the takbir (saying Allahu Akbar). , and these are the days of the ten. They remember Allah in them with takbir, and they repeat the takbir at night and day, and in the roads. So they are days of takbir, days of fasting, and days of worship. It is obligatory for the Muslim to utilize them in the virtues of deeds and drawing near to Allah (Glorified and Exalted is He). As for fasting in them, it is not obligatory; rather, it is a sunnah (recommended practice) and mustahabb (recommended), because it falls within the deeds about which He said, “There are no days in which righteous deeds are more beloved to Allah than these ten days.” Fasting falls within the deeds. It is narrated that he (peace and blessings be upon him) fasted the days of the ten, as it is in al-Muntaqa by al-Majd Ibn Taymiyyah, that the Prophet (peace and blessings be upon him) used to fast the ten days of Dhu al-Hijjah.