The word udhiyah means an animal of the an`am class (i.e., camel, cow, sheep or goat) that is slaughtered during the days of `Eid Al-Adha as an act of worship with the intention to draw closer to Allah.
This is one of the rituals of Islam prescribed in the Book of Allah and the Sunnah of His Messenger (peace and blessings be upon him), and according to the consensus of the Muslims.
In the Qur’an Allah says, (Therefore turn in prayer to your Lord and sacrifice (to Him only)) (Al-Kawthar 108: 2).
In the Sunnah it was narrated in Sahih Al-Bukhari and Sahih Muslim that Anas ibn Malik (may Allah be pleased with him) said: “The Prophet (peace and blessings be upon him) sacrificed two white rams speckled with black. He slaughtered them with his own hand, said ‘Allahu Akbar,’ and put his foot on their necks.” (Sahih al-Bukhari)
In this regard, we would like to cite the following fatwa issued by the late Sheikh Ibn Baz, the former Mufti of Saudi Arabia, in which he states the following:
If anyone wants to offer a sacrifice and the month of Dhul-Hijjah has begun, either because the new moon has been sighted or because thirty days of Dhul-Qi`dah have passed, then it is haram (unlawful) for him to remove anything of his hair or nails or skin until he has slaughtered the sacrifice, because of the hadith of Umm Salamah (may Allah be pleased with her), according to which the Prophet (peace and blessings be upon him) said: “When you see the new moon of Dhul-Hijjah – according to another version, When the ten days (of Dhul-Hijjah) begin – and anyone of you wants to offer a sacrifice, let him refrain (from cutting) his hair and nails” (Reported by Ahmad and Muslim). According to another version, “…let him not remove anything from his hair and nails until he has offered the sacrifice.” And according to yet another version, “…he should not touch his hair or skin.” (Sahih Muslim)
If he forms the intention to offer the sacrifice during the first ten days of Dhul-Hijjah, then he should refrain from that from the moment he forms that intention, and there is no sin on him for anything he may have done before forming the intention.
The reason for this prohibition is that when the person who wants to offer the sacrifice joins the pilgrims in some of the rituals of Hajj— namely drawing closer to Allah by slaughtering the sacrifice—he also joins them in some of the features of ihram, namely refraining from cutting his hair, etc.
This ruling applies only to the one who is going to slaughter the sacrifice. It does not apply to the one on whose behalf a sacrifice is offered, because the Prophet (peace and blessings be upon him) is reported to have said, “If any one of you wants to offer a sacrifice…” He did not say, “… is going to have a sacrifice offered on his behalf.” And the Prophet (peace and blessings be upon him) used to offer the sacrifice on behalf of members of his household, and it is not narrated that he told them to refrain from that (i.e., cutting their hair and nails, etc.).
Based on this, it is permissible for the family of the person who is going to offer the sacrifice to remove their hair, nails, and skin during the first ten days of Dhul-Hijjah.
If the person who wants to offer the sacrifice does remove anything from his hair, nails, or skin, then he has to repent to Allah and not to do it again, but he does not have to offer any expiation, and that does not prevent him from offering the sacrifice as some people think. If he does any of those things out of forgetfulness or ignorance, or some hair falls unintentionally, then there is no sin on him. If he needs to remove it then he may do so, and there is no blame on him, such as if a nail breaks and it annoys him, so he cuts it, or if a hair gets in his eye and he removes it, or he needs to cut his hair in order to treat a wound and the like.