Is it obligatory to fulfill the vow "not to use kohl until the case is definitively concluded," despite the prolonged duration of the case and the need to adorn oneself for marriage, or is expiation permissible?

A vow to abandon using kohl (antimony) is not binding, and nothing is required of its maker according to the majority of scholars, because it is not a vow of an act of devotion, based on the Prophet's (peace be upon him) saying: "A vow is only that by which the Countenance of Allah is sought." Some scholars, however, are of the opinion that its maker has the choice between fulfilling it or expiating it with an oath's expiation. This latter view is more cautious. It is advised to abandon fulfilling this vow and to expiate for it, because using kohl is a Sunnah.