‏الأيمان : Hadeeth No:4054 Abu Huraira reported Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying: He who took an oath and (later on) found another thing better than that, he should do that which is better, and expiate for the vow (broken by him)....

‏الجهاد والسير‏ : Hadeeth No:4344 It has been reported by Salama b. al-Akwa': We fought the Battle of Hawazin along with the Messenger of Allaah (sallAllaahu alayhi wa sallam). (One day) when we were having our breakfast with the Messenger of Allaah (may peace he upon him), a man came riding a red camel. He made it kneel down, extra...