Musnad Ahmad 28:410

Muhammad ibn Ja’far narrated to us, Mu’ammar narrated to us, Ibn Shihab informed us, and ‘Abd al-Razzaq said: Mu’ammar informed us, from Ibn Shihab, from ‘Isa ibn Talhah, from ‘Abdullah ibn ‘Amr ibn al-‘As, who said: I saw the Messenger of Allah (may Allah bless him and grant him peace) standing on his riding beast at Mina. He said: A man came to him and said: "O Messenger of Allah, I used to think that the shaving (of the head) was before the slaughtering, so I shaved before I slaughtered." He said: "Slaughter, and there is no harm." He said: Then another came to him and said: "O Messenger of Allah, I used to think that the slaughtering was before the stoning, so I slaughtered before I stoned." He said: "Stone, and there is no harm." He said: He was not asked about anything that a man had performed before another (in sequence) except that he said: "Do it, and there is no harm." ‘Abd al-Razzaq said: And another came to him and said: "O Messenger of Allah, I used to think that the shaving was before the stoning, so I shaved before I stoned." He said: "Stone, and there is no harm."