It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both); he said: We were with the Messenger of Allah (peace and blessings be upon him) on a journey when the time of sacrifice came, so we shared, seven people in one cow and ten people in one camel. This hadith is sahih (authentic) on the condition of Imam Bukhari, but the two Shaykhs (Bukhari and Muslim) did not record it.