Sayyiduna Mikhnaf bin Sulaym (may Allah be pleased with him) said: I reached the Prophet (peace and blessings be upon him) on the day of Arafah while he was saying: "Do you know it?" I do not know what the people answered him. Then the Prophet (peace and blessings be upon him) said: "It is due upon every household that they slaughter a sheep every Rajab, and also a sheep at every sacrifice (Eid al-Adha)."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17871