Sunan Ibn Majah
3150
Sahih+3

It was narrated from Umm Salamah that the Messenger of Allah (ﷺ) said:“Whoever among you sees the new crescent of Dhul-Hijjah and wants to offer a sacrifice, let him not take anything from his hair or nails.”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi