Musnad Ahmad 96:1

Ibrahim ibn Abi al-Abbas narrated to us, he said: Baqiyyah narrated to us, he said: Uthman ibn Zafar al-Juhani narrated to me, he said: Abu al-Ashadd al-Sulami narrated to me, from his father, from his grandfather, who said: I was the seventh of seven with the Messenger of Allah, may Allah bless him and grant him peace. He said: So he ordered us to collect one dirham for each man among us, and we bought a sacrificial animal for seven dirhams. We said: "O Messenger of Allah, we have paid a high price for it." The Prophet, may Allah bless him and grant him peace, said: "Indeed, the best of sacrificial animals are the most expensive of them and the fattest of them." The Messenger of Allah, may Allah bless him and grant him peace, gave an order, so one man took a leg, another man took a leg, one man took a hand, another man took a hand, one man took a horn, and another man took a horn, and the seventh slaughtered it, and we all said the takbir over it.