Abu Dawud
Oaths and Vows
Book Number: 015 / Hadith Number: 3268
Narated By Abdullah ibn Amr ibn al-'As : The Apostle of Allah (pbuh) said: An oath or a vow about something over which a human being has no control, and to disobey Allah, and to break ties of relationship is not binding. If anyone takes an oath and then considers something else better than it, he should give it up, and do what is better, for leaving it is its atonement.