Making a Vow to Fast without Specifying the Time and the Number of Fasts
Issue No. 2284- If a person vows that he will fast, without specifying the time and the number of fasts, it will be sufficient if he observes fast on one day. Similarly, if he makes a vow that he will offer prayer, but does not specify its number and details, it will be sufficient if he offers a two-rak‘at prayer. This order will also apply to vows for other good acts.