Yahya related to me from Malik that Abdullah ibn Dinar said, "Iheard Abdullah ibn Umar recite from the Qur'an, 'Prophet! When youdivorce women, divorce them at the beginning of their idda.'"Malik said, "He meant by that, to make one pronouncement of divorce atthe beginning of each period of purity."
USC-MSA web (English) reference: Book 29, Hadith 79
Arabic reference: Book 29, Hadith 1241