Mukhtasar Muslim

Abu Huraira (may Allah be pleased with him) reports that a man was delayed at night with the Messenger of Allah (peace and blessings be upon him), then when he went to his home, he saw that his children had fallen asleep. His wife brought food, so he swore an oath that he would not eat because of his children. Then he thought it appropriate to eat and so he ate. Later, he came to the Messenger of Allah (peace and blessings be upon him) and informed him, so the Messenger of Allah (peace and blessings be upon him) said: Whoever swears an oath about something, but then sees something else better than it, should do that which is better and give expiation for his oath.