«من رأى منكم هلال ذي الحجة وأراد أن يضحي فلا يأخذن من شعره ولا من أظافره حتى يضحي»
The Prophet (peace and blessings be upon him) said:
"Whoever sees the new moon of Dhu al-Hijjah and intends to offer a sacrifice, let him not cut his hair or his nails until he has offered the sacrifice."
Hadith Referenceصحیح الجامع الصغیر / حرف الميم / 6251