Abu Dawud Book 9, Hadith Number 2785.

Chapter : On a man who shaves his hair during the first ten days of dhu alhijjah while he intends to do sacrifice.

Narated By Umm Salamah : The Apostle of Allah (PBUH) said: If anyone has sacrificial animal and intends to sacrifice it, and he sights the new moon of Dhu al-Hijjah, he must not take any of his hair and nails until he sacrifices.

Abu Dawud said: The name ‘Amr b. Muslim in the chain narrated by Malik and Muhammad b. ‘Amr is disputed. Some say that it is ‘Umar and the majority holds that it is ‘Amr.

Abu Dawud said: He is ‘Amr b. Muslim b. Ukaimah al-Laithi al-Jundu’i.