Sunan an-Nasa'i, Volume 5, Book 43, Hadith 4369 (DarusSalam) ⓘ
It was narrated from Umm Salamah that the Messenger of Allah said: "when the (first) ten (days of Dhul-Jijjah) begin, and one of you wants to offer a sacrifice, let him not remove anything from his hair or skin."
أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ عَبْدِ الرَّحْمَنِ، قَالَ حَدَّثَنَا سُفْيَانُ، قَالَ حَدَّثَنِي عَبْدُ الرَّحْمَنِ بْنُ حُمَيْدِ بْنِ عَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أُمِّ سَلَمَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِذَا دَخَلَتِ الْعَشْرُ فَأَرَادَ أَحَدُكُمْ أَنْ يُضَحِّيَ فَلاَ يَمَسَّ مِنْ شَعْرِهِ وَلاَ مِنْ بَشَرِهِ شَيْئًا " .
also referenced under: Hadith 4364 (Reference) & Book 43, Hadith 4 (In-Book)