Ibn ‘Abbas (may Allah be pleased with him and his father too) narrated that the Prophet (prayers and peace of Allah be upon him) said: “No good deeds done on other days are liked by Allah than the ones done on these (first ten days of Dhul-Hijja).” Then some companions of the Prophet said, “Not even Jihad?” He replied, “Not even Jihad, except that of a man leaves for the sake of Allah (Jihad) with his self and his money and does not return with any of those things” [Reported by Al-Bukhari]
«ما العمل في أيام العشر أفضل من العمل في هذه،قالوا: ولا الجهاد ؟ قال: ولا الجهاد ، إلا رجل خرج يخاطر بنفسه وماله ، فلم يرجع بشيء»رواه البخاري
Performing Hajj and ‘Umra; they are the best things to be done in these days, and the excellence of performing them is proofed in many Ahadeeth including the saying of the Messenger of Allah (prayers and peace of Allah be upon him): “A ‘Umra is an expiation for the sins committed between it and the next, and Hajj which is accepted will receive no other reward than Paradise.” [Agreed upon]
«العمرة إلى العمرة كفارة لما بينهما، والحج المبرور ليس له جزاء إلاّ الجنّة» متفق عليه
Fasting all these days, or some of them, especially the day of ‘Arafa, because Muslim reported on the authority of Abu Qatada that the Prophet (prayers and peace of Allah be upon him) said: “I seek from Allah that fasting on the day of ‘Arafa may atone for the sins of the preceding and the coming years.” [Narrated by Ibn Majjah, and authenticated by Al-Albani]
«صيام يوم عرفة أحتسب على الله أن يكفر السنة التي قبله والتي بعده»رواه ابن ماجه وصححه الألباني
Repenting and abstaining from doing the sins to achieve forgiveness and mercy as a consequence to doing the good deeds. Actually, the sins are the reason of being driven away from Allah and being expelled. On the other hand, the acts of obedience are the reason of having nearness with Allah and kindness. Abu Hurayra (may Allah be pleased with him) narrated that the Prophet (prayers and peace of Allah be upon him) said: “Allah feels jealousy, and his jealousy is when the believer commits what He forbade” [Agreed Upon]
«إن الله يغار، وغيرة الله أن يأتي المؤمن ما حرم الله» متفق عليه
Muslim and others reported on the authority of Umm Salama (may Allah be pleased with her) narrated that the Prophet (prayers and peace of Allah be upon him) said: “He who has a sacrificial animal with him whom (he intends) to offer as sacrifice, and the month of Dhul-Hijja approaches, he should not take from his hair or trim his nails.” [Reported by Muslim]
«إذا رأيتم هلال ذي الحجة وأراد أحدكـم أن يضحّي فليمسك عن شعره وأظفاره»رواه مسلم
And in another narration: “He should not take from his hair or trim his nails until he has sacrificed the animal”.” It is clear from the apparent meaning that this prevention is for the owner of the sacrifice only and does not include the wife or the children, except if one of them has a private sacrifice.
«فلا يأخذ من شعره ولا من أظفـاره شيئاً حتى يضحّي»
Doing much of the good deeds (i.e. prayers, giving charity, fighting in the cause of Allah, reciting the Holy Quran, enjoining the good and forbidding the evil …etc,) which have their rewards multiplied in these days.
The Muslim should observe Eid prayer in its place and attend the ceremony, which is after the prayer, and take lessons from it. Moreover, he has to know the wisdom of Eid prayer and know that it is a day of gratitude and doing good deeds, it is not a day of evil or season for committing the sins.
Sacrificing the animals should be done on the Day of Sacrifice (10th of Dhul-Hijja) and on the days of Tashriq (11th, 12th and 13th of Dhul-Hijja). It is the Sunnah of our father, Ibrahim (peace be upon him) when Allah ransomed his son with a great sacrifice. And it has been reported that “The Prophet sacrificed with his own hands two horned full grown rams reciting the name of Allah and glorifying Him (saying Allahu Akbar). He placed his foot on their sides (while sacrificing)” [Agreed Upon]