Sayyiduna Mikhnaf bin Sulaym (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) addressed us at Arafah and said: "Upon every Muslim household a sacrifice (udhiyah) and an 'atirah are obligatory. Do you know what the 'atirah is? It is the one you call the Rajabiyyah."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17869
Sayyiduna Mikhnaf bin Sulaym (may Allah be pleased with him) said: We were standing with the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said: "O people! Indeed, upon every household, every year, a sacrifice and an 'atirah are obligatory. Do you know what the 'atirah is? It is the one that people call the Rajabiyyah."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17870
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