Al-Sha'bi narrates from Hudhayfah bin Asid (may Allah be pleased with him), who said: I saw Abu Bakr and Umar (may Allah be pleased with them both) not offering the sacrifice, for fear that people would follow them in it and make it an (obligatory) practice. Then my family drew me away from the Sunnah even though I knew it, so much so that now I offer a sacrifice on behalf of every single member.
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3045