Sunan an-Nasa'i 4361
سنن النسائي#4361SahihIt 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
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih Muslim
In-book reference: 43:1