Lady Aisha (may Allah be pleased with her) narrates that I heard the Prophet Muhammad (peace and blessings be upon him) say: "Whoever does not have a sacrificial animal with him should fast for three days before the sacrifice, and whoever is unable to fast during these three days should fast during the days of Tashreeq (i.e., the days in Mina)." The narrator of this narration, Yahya bin Abu Anisah, is weak.