Question :

Is it permissible for a person, who vowed to offer two Rak`ahs(units of prayer) everyday for Allah`s sake, to do so after the Fajr(dawn) prayer?

The Answer :

In principle, a vow should be fulfilled as it was originally intended, and if its time lapses then, it should be fulfilled at any time because of the vow. Therefore, it is permissible to offer them after the Fajr prayer, and there is no prohibition in doing so. However, it is preferable for him to offer these two Rak`ahs at some other time to avoid the disagreement amongst the scholars in this regard.