Question: Is the Prophet (peace be upon him) authentically reported to have observed Sawm for the first ten days of Thul-Hijjah?
Answer: It is not authentically reported that the Prophet (peace be upon him) observed Sawm the first ten days of Thul-Hijjah – better described as the nine days preceding `Eed-ul-Ad-haa (the Festival of the Sacrifice). However, he (peace be upon him) urged people to do good deeds during these days. The Prophet (peace be upon him) is authentically reported to have stated: “No good deed performed on other days are superior to those performed during these (first ten days of Thul-Hijjah).”.. read more here.
Question 17: What is the religious ruling on observing Sawm (Fasting) on the last Ten Days of Thul-Hijjah and the whole of the months of Muharram and Sha‘baan? Answer us, may Allaah confer His Blessings upon you!
Answer: Bismillaah [In the Name of Allaah] and all praise is due to Him. It is Mashroo‘ (Islaamically permissible) to fast in the month of Muharram and Sha‘baan. As for the last Ten Days of Thul-Hijjah, there is no evidence concerning fasting on them; but there is nothing wrong with fasting on them without having the belief that they have certain specialty or fasting is recommended on them in particular.The Prophet (peace be upon him) said concerning the month of Muharram: The best Sawm after Ramadaan, is the Month of Allaah: Muharram.Therefore, it is recommendable to fast the whole of Muharram and it is Sunnah (supererogatory act of worship following the example of the Prophet) to fast on the ninth, the tenth and the eleventh of it... read more here.
Question 81: I fasted on the day of `Arafah (9th of Thul-Hijjah) intending to make up for a day I missed in Ramadaan. Does fasting the Day of `Arafah (9th of Thul-Hijjah) suffice, if I intended it to make up for the missed day or not?
Answer: It is permissible for you to fast the Day of `Arafah (9th of Thul-Hijjah) intending to make up for a missed day of Ramadaan… read more here.