" مَنْ رَأَى هِلاَلَ ذِي الْحِجَّةِ فَأَرَادَ أَنْ يُضَحِّيَ فَلاَ يَأْخُذْ مِنْ شَعْرِهِ وَلاَ مِنْ أَظْفَارِهِ حَتَّى يُضَحِّيَ "
It was narrated from Ummm Salamah that the Prophet said: "Whoever sees the new crescent of Dhul-Hijjah and wants to offer a sacrifice, let him not remove any of his hair or nails until he has offered the sacrifice."