Swearing not to eat watermelon and then eating

Q 2: A Muslim brother wanted to give me a watermelon, and I swore by Allah that I would not take it, but I later did. What is the kind of this oath? Do I have to pay Kaffarah (expiation)?

A: If a person swears by Allah or by one of His Attributes on purpose about a possible future event, it will be considered an oath bound by intention. As you have not sworn to commit a sin, you should abide by your oath. If you want to break it, and think it is better to do so, you have to pay Kaffarah for breaking your oath, which is feeding ten needy people by giving each a kilo and a half of rice or of the usual kinds of food in the country, clothing them or emancipating a believing slave. If you cannot do either, you should observe Sawm (fasting) for three days. This is proven by (Part No. 23; Page No. 194) what was related by Al-Bukhari in his Sahih (authentic) Book of Hadith, volume 7, p. 216, on the authority of `Abdul-Rahman ibn Sumrah, that the Prophet (peace be upon him) said, O, `Abdul-Rahman ibn Samurah! Do not ask for leadership, for if you ask for it, you will carry its burden, while if you do not ask for it, you will be helped with it. If you make an oath, and then find a better alternative, expiate for your oath and go for the better alternative. We recommend that you do not make oaths too often, according to Allah's saying, And protect your oaths (i.e. do not swear much). And His saying, And make not Allâh’s (Name) an excuse in your oaths against your doing good and acting piously May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.