It wasnarrated that Muhammad bin Sirin said:
"I asked Ibn 'Umaraboutsacrifices and whether they are obligatory. He said: 'TheMessengerof Allah (ﷺ) and the Muslims after him offered sacrifices,and thisis the Sunnah.'" (IT)
English reference (IT): Vol. 4, Book 26, Hadith 3124 (IT)
Arabic reference (IT): Book 26, Hadith 3243 (IT)