Abu al-Ashadd al-Sulami narrates from his father, from his grandfather (may Allah be pleased with him): I was the seventh of seven with the Messenger of Allah (peace and blessings be upon him). The Messenger of Allah (peace and blessings be upon him) gave us an order, and each man among us collected a dirham, 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 (peace and blessings be upon him) said: "The best of sacrifices are the most costly and the most precious of them." Then the Messenger of Allah (peace and blessings be upon him) ordered one man to take hold of a foreleg, another of a foreleg, another of a hind leg, another of a horn and another of a horn, and the seventh slaughtered it, and we all said the takbir over it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19050