The Book of Sacrifices - Sahih Muslim 1977g

He who has a sacrificial animal with him whom (he intends) to offer as sacrifice, and he enters the month of Dhu'l-Hijja, he should not get his hair cut or nails trimmed until he has sacrificed the animal.

Scholarly Commentary

This noble hadith establishes a sacred prohibition for those who intend to perform the udhiyah (sacrificial offering). When the crescent of Dhu'l-Hijja is sighted and one possesses an animal designated for sacrifice, it becomes forbidden for them to remove any hair from their body or trim their nails.

The wisdom behind this prohibition lies in the complete offering of oneself to Allah. Just as the sacrificial animal is presented whole and untouched, the person offering it should maintain their natural state, symbolizing their total submission. Every part of the believer becomes connected to the act of worship during these blessed days.

This ruling applies specifically from the beginning of Dhu'l-Hijja until after the sacrifice is completed. If one intentionally violates this prohibition, they must seek Allah's forgiveness, though most scholars hold there is no required expiation. The best course is to maintain this state as an act of obedience and in emulation of the Prophet's guidance.

Jurisprudential Rulings

The prohibition encompasses all body hair removal (head, beard, underarms, pubic area) and nail trimming of both hands and feet. Shaving, cutting, clipping, or any method of removal is included in the prohibition.

This ruling applies only to the person who owns the sacrificial animal. Family members not owning their own separate sacrifice are not bound by this prohibition, though it is commendable for them to follow suit.

If one forgets and trims hair or nails, or does so out of necessity (such as medical requirement or removal of harmful hair), they are excused but should discontinue once they remember.