Husband swearing to divorce his wife if she sees his sister at her house. Is this divorce effective if his sister comes to his house?

A: There are different views reported from Imam Ahmad concerning the person who does something having forgotten that he has taken an oath of divorce not to do. The more established view in this regard is (Part No. 20; Page No. 112) that he did not break the oath by doing the action forgetfully and his oath is still effective. This is the view of `Ata', `Amr ibn Dinar, Ibn Abu Nujayh, Is-haq and Ibn Al-Mundhir. This is also the preponderant view of Al-Shafi`y Madh-hab (school of Jurisprudence) as mentioned in "Al-Khulasah". It is said in "Al-Furu`": This is the preponderant opinion. It is said also in "Al-Insaf": It is the soundest opinion. Shaykh Al-Islam, Ibn Taymiyyah, chose this opinion based on the statement of Allah (Exalted be He): And there is no sin on you concerning that in which you made a mistake, except in regard to what your hearts deliberately intend. The Prophet (peace be upon him) also said, "Allah overlooks what my people do by mistake, forgetfully and under coercion." It should be noted that the man did so unintentionally and he did not break his oath intentionally similar to the one sleeping or the insane whose errors are pardoned. Accordingly, in such a case, the man and his wife did not break the oath due to their forgetfulness and the oath is still effective. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.