A person took an oath that he will not fast. Thereafter, he made the intention to fast. If he fasts for even a second, his oath will break. By his taking an oath not to fast does not mean that he has to fast the entire day. By breaking his fast even after a little while, he will have to give kaffarah for breaking his oath. If the person says: “I will not even keep one fast”, his oath will break at the time of the end of the fast. As long as the time of fasting does not come to an end, his oath will not break. If the person breaks his fast before the end of the day, his oath will not break.
A person took an oath that he will not offer his salaat. Thereafter, he regretted this and stood up to offer his salaat. The moment he makes the sajdah for the first rakaat, his oath will break. His oath will not break prior to making the first sajdah. If he breaks his salaat after the first rakaat, even then his oath will break. It should be remembered that it is a major sin to take oathsof this nature. If a person takes such oaths, he should immediately break them and pay the kaffarah for them.