(1) Reported by al-Bukhari, 1/226, Book of Ablution, chapters “Washing the limbs once” and “Wiping over the whole head”; by Muslim, nos. 235–236, Book of Purification, chapter “The Prophet’s wudu”; by Malik, 1/18; by Abu Dawud, nos. 118–120; by al-Tirmidhi, nos. 35 and 47; and by al-Nasa i, 1/71-72. (2) A ḥarra is a tract of land covered with black volcanic stones; most of the ḥarras surround the Prophet’s city. The ḥarra intended here is Ḥarra Waqim, the eastern of the two basalt fields of Madina where the battle took place, hence the episode is named after it. Its cause was that the notables of Madina revoked their oath of allegiance (bay a) to Yazid b. Mu awiya because of his misconduct. Yazid dispatched an army under Muslim b. Uqba al-Murri; the two sides met outside Madina on the 27th of Dhu l-Hijja 63 AH. The people of Madina were defeated, and many eminent Muslims—including surviving Companions and leading Successors—were killed, either in open combat or executed afterwards. See: Ibn Khaldun, al- Ibar, 1/67-68. This engagement ranks among the gravest calamities and breaches suffered by the Muslim community. (*) Musnad Ahmad, 6/452; Ibn Sa d, al-Tabaqat, 8/280, 285; Ibn Qutayba, al-Ma arif, 171, 173, 210, 282, 555; Ibn Abd al-Barr, al-Istidhkar, 4/1784; Ibn al-Athir, Usd al-ghaba, 7/14; al-Mizzi, Tahdhib al-kamal, 1677; al-Dhahabi, Tadhhib al-tahdhib, 4/2/256; al-Dhahabi, Tarikh al-islam, 2/273; al-Haythami, Majma al-zawa id, 9/260; Ibn Hajar, Tahdhib al-tahdhib, 12/398-399; Ibn Hajar, al-Isaba, 12/116; al-Dhahabi, Khulasat tadhhib al-kamal, 488; Ibn al-Imad, Shadhar t al-dhahab, 1/15, 48. (3) The autograph and Usd al-ghaba read “Ma bad” with a b; Ibn Hajar, however, vocalises it in al-Isaba, 12/116, without the b, i.e. “Ma d,” rhyming with “Sa d.” This is also the form found in Ibn Sa d’s Tabaqat, 8/280; al-Jamhar a f nasab al-Arab, 390; and al-Istidhkar, 4/1784.