I asked Abu Ayub al-Ansari how the sacrifices were during the time of the Messenger of Allah ﷺ.He replied, "A man would sacrifice a single sheep on behalf of himself and his household. They would eat from it and feed others, until people began to compete with one another in showing off, and it became as you now see."
سألت أبا أيوب الأنصاري كيف كانت الضحايا على عهد رسول الله ﷺ؟ فقال: كان الرجل يضحي بالشاة عنه، وعن أهل بيته فيأكلون ويطعمون حتى تباهى الناس فصارت كما ترى.
Tirmidhi (1505) and Ibn Majah (3147) narrated it through Dahhak bin Uthman, who said, Umarah bin Abdullah bin Sayyad narrated to me, from Ata bin Yasar, who said, and then he related it. Its chain of transmission is sahih. Tirmidhi said, "This is a hasan sahih hadith."Malik also narrated it in the chapter on sacrifices (1377, in the version of Abu Musab) from Umarah bin Sayyad, in a shortened form that does not include Ata's question to Abu Ayub. In the version of Yahya Al-Laythi (10) it appears as Umarah bin Yasar, which is a mistake.