If he cuts his hair during the first ten days of Dhu’l-Hijjah, he has done something wrong but his sacrifice is still valid
Shaykh Ibn ‘Uthaymeen said:
Yes, his sacrifice will be accepted but he will be a sinner. With regard to a widespread belief among the common people that if a man removes anything from his hair, nails or skin during the first ten days of Dhu’l-Hijjah, his sacrifice is not valid, this is not correct, because there is no connection between the validity of his sacrifice and his removing anything from these three things.
Al-Sharh al-Mumti’, 7/533
And Allaah knows best.
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