Al-Ma'idah 5:89 لا يواخذكم الله باللغو في ايمانكم ولاكن يواخذكم بما عقدتم الايمان فكفارته اطعام عشرة مساكين من اوسط ما تطعمون اهليكم او كسوتهم او تحرير رقبة فمن لم يجد فصيام ثلاثة ايام ذالك كفارة ايمانكم اذا حلفتم واحفظوا ايمانكم كذالك يبين الله لكم اياته لعلكم تشكرون ٨٩

Allah will not call you to account for what is futile in your oaths, but He will call you to account for your deliberate oaths: for expiation, feed ten indigent persons, on a scale of the average for the food of your families; or clothe them; or give a slave his freedom. If that is beyond your means, fast for three days. That is the expiation for the oaths ye have sworn. But keep to your oaths. Thus doth Allah make clear to you His signs, that ye may be grateful.