Yazid bin Hayyan al-Taymi narrates that he heard Sayyiduna Zayd bin Arqam (may Allah be pleased with him) when he was asked: "Who are the family of Muhammad (peace and blessings be upon him)?" He said: "Those for whom charity (sadaqah) is forbidden." It was asked: "Who are they?" He said: "The family of Ali, the family of Aqil, the family of Ja'far and the family of al-Abbas."
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 5004