Does taking from the hair and nails before the sacrifice affect the validity of the sacrifice?

Abstaining from cutting hair and trimming nails is not a condition for the validity of the sacrifice (udhiyah), nor does taking from them invalidate the sacrifice. There is no disagreement among scholars on this issue. Rather, the disagreement revolves around the ruling on abstaining from these things for one who intends to offer a sacrifice: whether it is obligatory, recommended, or not recommended at all. There is no expiation (fidyah) for one who does so.