A woman gave her husband a promise that she would never marry anyone after him, until Allaah joined them by His mercy and grace. Does she have the right to marry anyone after him? Is this regarded as not fulfilling a promise which is one of the attributes of the hypocrites?.
It is permissible for this woman to marry after her husband dies, but she should offer expiation for her oath, because the Prophet (peace and blessings of Allaah be upon him) said: “By Allaah, if Allaah wills, I do not swear an oath then see something better than it but I will offer expiation for my oath and do that which is better.” Narrated by al-Bukhaari, 3133; Muslim, 1649. And he (peace and blessings of Allaah be upon him) said: “If you swear an oath then you see something that is better than it, offer expiation for your oath and do that which is better.”
Narrated by al-Bukhaari, 2622; Muslim, 1652.
Marriage is better for this woman then her remaining unmarried, because that serves many interests.