Majma al-Zawaid — Hadith 6056

It is reported about Sayyiduna Umar (may Allah be pleased with him) that a man asked him about eating rabbit. He said: "Call Ammar to me." Sayyiduna Ammar (may Allah be pleased with him) came, and Sayyiduna Umar (may Allah be pleased with him) said: "Narrate to us the hadith about the rabbit, from the day when we were with the Prophet (peace and blessings be upon him) at such-and-such a place." Sayyiduna Ammar (may Allah be pleased with him) said: A Bedouin presented a rabbit (its meat) as a gift to the Prophet (peace and blessings be upon him). The Prophet (peace and blessings be upon him) ordered those present to eat it. The Bedouin said: "I saw blood" (meaning it is a female rabbit and it menstruates). The Prophet (peace and blessings be upon him) said: "There is no harm in it." The Prophet (peace and blessings be upon him) said: "Come forward and eat it." He said: "I am fasting." The Prophet (peace and blessings be upon him) asked: "Which fast?" He replied: "I fast three days every month." The Prophet (peace and blessings be upon him) said: "Why do you not keep these (fasts) on the bright days?"
Abu Ya'la recorded it, and al-Tabarani in al-Mu'jam al-Kabir, and its chain has weakness.