Mukhtasar Muslim

Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) says: I came to the Messenger of Allah (peace and blessings be upon him) along with some Ash'aris to ask him for mounts. The Messenger of Allah (peace and blessings be upon him) said, "By Allah, I will not give you mounts, and I do not have any mounts to give you." Then we stayed there for as long as Allah willed. After that, some camels came to the Messenger of Allah (peace and blessings be upon him), so he ordered that three white-humped camels be given to us. When we left, we or some of us said, "May Allah not bless us, for we came to the Messenger of Allah (peace and blessings be upon him) and asked for mounts, and he swore that we would not get mounts, but then he gave us mounts." Then people came to the Messenger of Allah (peace and blessings be upon him) and told him, so he said, "I did not mount you, but Allah mounted you. And if I ever swear an oath and then see something better than it, I will offer expiation for my oath and do what is better."

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.