Al-'Ala narrated from Muhammad ibn Muslim from one of the Imams عليه السلام that he said: "One should perform the ritual bath (ghusl) on three nights in the Month of Ramadan: the nineteenth, the twenty-first, and the twenty-third. The Commander of the Faithful عليه السلام was struck on the nineteenth and passed away on the twenty-first." Imam عليه السلام added: "The ghusl should be performed at the beginning of the night, and it suffices until its end."