All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
In case of making an oath to do something and breaking it, then this oath becomes no longer effective and the matter goes back to the state it was before. If this matter is permissible in principle, one may do it or to leave it, and if it is mandatory, then it remains on the principle that it is an obligation to do it before and after making the oath. However, if this matter is forbidden, it is not permissible to do it neither before breaking the oath nor after breaking it. For example, if a person makes an oath to quit smoking – and it is known that smoking is forbidden and quitting it is an obligation – then it becomes forbidden for him to smoke and he is obliged to quit it whether or not he broke his oath and expiated for it.
For instance if he made an oath not to drink tea or coffee, he is not obliged to fulfill this oath and stop drinking tea and coffee; rather, drinking tea and coffee still remains permissible for him before breaking his oath and after breaking it and after expiating for it.
Moreover, in case a person does what he made an oath not to do and then he did it and expiated for it, and then he did it again, he is not obliged to expiate for it a second time because once the oath is broken it is no longer effective unless one intended (when making his oath) to expiate every time he does something or fails to do it, or that he said an expression that implies the repetition of this thing, like if he says ‘every time I do this thing or fail to do it, I have to expiate for it’, in which case, he is obliged to expiate for doing that thing or failing to do it.
Allaah Knows best.