Salman Abu Hazam al-Ashja'i سلمان أبو حازم الأشجعي · Chapters on Sacrifices

“I asked Ibn ‘Umar about sacrifices and whether they are obligatory. He said: ‘The Messenger of Allah (ﷺ) and the Muslims after him offered sacrifices, and this is the Sunnah.’” Another chain reports exactly the same.