Growing up I didn’t know much about the first 10 days of Dhul Hijjah. I knew about Hajj and that was about it. Later on in my life I found out about the importance of fasting on the 9th day of Dhul Hijjah. Recently I found out the importance of the 10 days. I have included some notes taken from ‘I got it covered’ and IslamQA (link provided) and have also included a 10 minute lecture on the virtues of the 10 days.
The Prophet (peace be upon him) also said: “There is no deed that is better before Allah or more greatly rewarded than a good deed done in the (first) ten days of al-Adha.” He was asked: “Not even jihad for the sake of Allah?” He said: “Not even jihad for the sake of Allah, unless a man goes out himself for jihad taking his wealth with him and does not come back with anything.” [Al-Daarimi, 1/357]
Thus, the ten days are better than all other days of the year, therefore, whoever is not able to go to Hajj should use this blessed time to complete even more righteous deeds than usual. These can include anything such as giving charity, honouring one’s parents, upholding the ties of kinship, and enjoining what is good and forbidding what is evil. Fasting and remembrance are particularly recommended:
1. Fasting Nine days, especially on the Day of ‘Arafah
It is Sunnah for the Muslim to fast on the first nine days of Dhul-Hijjah, because fasting is one of the best of deeds. In a hadith qudsi, Allah says: “All the deeds of the son of Adam are for him, except fasting, which is for Me and I shall reward for it.” [Bukhari, 1805] The Prophet (peace be upon him) used to fast on the first nine days of Dhul-Hijjah. The Prophet (peace be upon him) said, “The Prophet used to fast on the first nine days of Dhul-Hijjah and the day of Ashura, and three days each month, the first Monday of the month and two Thursdays.” [Abu Dawood, 2/462] The ten days of Dhul-Hijjah include Yawm al-`Arafah (the Day of `Arafah), on which Allah perfected His Religion. The Prophet (peace be upon him) said: “Fasting the day of `Arafah expiates the sins of two years: the past one and the coming one. Fasting on the day of Ashura expiates the sins of the past year.” [Muslim]
It is Sunnah to recite remembrances known as the takbeer, tahmeed, tahleel, and tasbeeh during the first ten days of Dhul-Hijjah, saying these words out loud in the mosques, homes, streets and every place in which it is permissible to remember Allah.
Takbeer: Allahu akbar (God is most great)
Tahmeed: Al-hamdu Lillah (All praises be to God)
Tahleel: Laa ilaha ill-Allah (There is no god but Allah)
Tasbeeh: Subhaan-Allah (Glory be to God),
The Prophet (peace be upon him) explained how, “There are no days that are greater before Allah or in which good deeds are more beloved to Him, than these ten days, so recite a great deal of tahleel, takbeer and tahmeed during them.” [Ahmad, 7/224]
Here is a detailed explanation on the virtues of the 10 days