Abu al-Ahwas narrates from Sayyiduna Abdullah (may Allah be pleased with him): The Sunnah way of divorce is that a divorce is given in each period of purity. When it is the last of these, that is the waiting period that Allah, the Lord of Might, has commanded.
(b) Hafs bin Ghiyath mentions from al-A'mash: We consider it recommended to divorce in this way.
(c) Masruq (may Allah have mercy on him) says: A man asked Sayyiduna Abdullah (may Allah be pleased with him): A man has given his wife a hundred divorces. He said: She has become separated by three, and all the rest are a means of disobedience.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الخلع والطلاق / 14947