Yahya related to me from Malik from Ibn Shihab from clsa ibnTalha that Abdullah ibn Amr ibn al-As said, "The Messenger of Allah,may Allah bless him and grant him peace, stopped for the people atMina, and they questioned him and a man came and said to him,'Messenger of Allah, I was unclear about what to do and I shavedbefore sacrificing,' and the Messenger of Allah, may Allah bless himand grant him peace, said, 'Sacrifice, and don't worry.' Then anothercame to him and said 'Messenger of Allah, I was unclear about what todo and I sacrificed before throwing the stones.' He advised, 'Throw,and don't worry.' "Amr continued, saying that the Messengerof Allah, may Allah bless him and grant him peace, was not asked aboutanything done before or after without his saying, "Do it, and don'tworry."
USC-MSA web (English) reference: Book 20, Hadith 251
Arabic reference: Book 20, Hadith 947