Ihaab Abduh, in his book استحالة وجود النسخ بالقرآن, pages 168-169, states that the majority of the scholars have said that a man may divorce his wife without witnesses, and they said that there is no evidence from the Sunna or the sayings of the Sahaaba that witnesses are required. Ihaab counters with
which clearly require two witnesses of the divorce and emphasize that ruling with the words ذلكم يوعظ به من كان يؤمن بالله واليوم الآخر
(With that are instructed those who believe in God and the Final Day).
Ihaab refers to the scholars opinions as quoted in Sayyid Saabiq's famous book فقه السنة (Jurisprudence of the Sunna). I looked it up and here is a summary of what Saabiq wrote,
- The majority said that because divorce is the right of the man only, no witnesses are necessary for him to assert his right. What logic is that?
- No report from the Prophet or the Sahaaba that witnesses are required. How about the Quran? There is no need for a report. How can the Prophet (PBUH) or the Sahaaba say differently from the Quran?
- Imaami Shia quote 65:2 as evidence that two witnesses are required for divorce.
- Ali, Imraan ibn Haseen, Al-Baaqir, Ja`far As-Saadiq, `Ataa', Ibn Jurayj, Ibn Seereen all said that witnesses of divorce are required.
- Saabiq said that what the scholars claim to be a consensus is a consensus of scholars of one school of thought, not a proper consensus. I say this applies to countless juristic issues where consensus is claimed.
Aside from the obvious, that no consensus can possibly abrogate the Quran
(or the Sunna for that matter), the opinions quoted above prove that 65:2 was not abrogated. Abrogation is not done by failure to make a new ruling, it's done by a new ruling that explicitly cancels an old one!