*This article was written by Imam Mustafa Umar and was originally published on his website, mustafaumar.com, here.
I begin in the name of Allah, the most kind and merciful:
Scholars, past and present, have differed over this issue, so it should not be turned into a matter of dispute. It appears to me that refraining from cutting/removing any hair or nails on the body is recommended for those who intend to sacrifice an animal, whether they will slaughter the animal themselves or are commissioning someone to do it for them. However, whoever decides to do so will not incur any sin. The person who will be slaughtering for another does not need to refrain from anything since they are not doing it for themselves.
The wisdom behind this could be that a person who is offering a sacrifice wants to resemble a person performing Hajj since it is about sacrifice, so they refrain from cutting the hair and nails to further the resemblance [since pilgrims to Makkah are also not allowed to cut].
Reason for the Difference of Opinion
Pieces of Evidence
A: The prophetic report narrated by Umm Salamah states: “Whoever sights the crescent for the month of Dhul Ḥijjah and intends to sacrifice an animal should cut neither his hair nor his nails.”
B: The prophetic report narrated by ʿĀ’ishah that: “…the Prophet sent a sacrificial animal to the Kaʿbah [while residing at Madīnah] but did not abstain from anything [that a person performing Ḥajj would abstain from]…”
Scholars who said it is forbidden for a person who intends to slaughter: Saʿīd ibn al-Musayyib, Rabīʿah, Aḥmad ibn Ḥambal, Dāwūd, Ibn Ḥazm, Isḥāq, some Shāfiʿī scholars, and Ṭaḥāwī [of the Ḥanafī school]. Among the later scholars who upheld this opinion: Ibn Qayyim al-Jawziyyah, Ibn Qudāmah, al-Shawkānī, Ibn Bāz, and Ibn al-Uthaymīn.
REASONING BEHIND THE FIRST OPINION
- Report A is authentic.
- Report B is confined to only those who send a sacrificial animal, not those who sacrifice within their own city.
- Report A must be taken literally because even if it was considered to be disliked and not prohibited, the Prophet would never do something which is disliked.
Scholars who said it is disliked but not prohibited: al-Shāfiʿī and some of Aḥmad ibn Ḥambal’s students [such as Abū Yaʿlā]. Among the later scholars who upheld this opinion: al-Nawawī.
REASONING BEHIND THE SECOND OPINION
- Both reports A and B are authentic and appear to be contradictory because they are speaking about the same issue.
- It is best to reconcile both reports by saying that report A is not to be taken literally but rather as something disliked but not prohibited.
Scholars who said that there is nothing wrong with cutting the hair or nails: Abū Ḥanīfah and his students, Mālik and his students, and Sufyān al-Thawrī.
REASONING BEHIND THE THIRD OPINION
- Report A has some weakness in it so report B takes precedence over it.
- Report A doesn’t make sense because it is contrary to analogy. If a person was supposed to refrain from cutting their nails and hair, they should have also been instructed to refrain from certain clothing, perfume, and intimacy because that is what people who are performing Hajj must also do.
There is clearly a legitimate difference of opinion due to both the clarity and authenticity of the two reports in question.
 Sharḥ al-Nawawī ʿalā Muslim 13:138-139. Al-Nawawī mentioned another possible reason as well which I prefer not to mention here.
 Muslim 3:1565, Abū Dā’ūd 3:94, Tirmidhī 4:102, Nasā’ī 7:211.
 Bukhārī 7:102, Muslim 2:957.
 al-Tirmidhī 4:102, Tuḥfah al-Aḥwadhī 5:99-100, Sharḥ Mushkil al-Āthār 14:141-143.
 `Awn al-Maʿbūd wa Ḥāshiyah ibn al-Qayyim ʿalā Sunan Abī Dāwūd 7:346, al-Istidhkār 4:84.
 Tuḥfah al-Aḥwadhī 5:99-100, `Awn al-Maʿbūd wa Ḥāshiyah ibn al-Qayyim ʿalā Sunan Abī Dāwūd 7:346.
 Tuḥfah al-Aḥwadhī 5:99-100, al-Istidhkār 4:84.
 `Awn al-Maʿbūd wa Ḥāshiyah ibn al-Qayyim ʿalā Sunan Abī Dāwūd 7:347.