Sahih Muslim | Book 15 | Hadith Number 4060

Narrated by Tamim b. Tarafa
Tamim b. Tarafa reported that he heard 'Adi b. Hatim say that a person came to him and asked for one hundred dirhams. He ('Adi) said: You asked Me for one hundred dirhams and I am the son of Hatim; by Allah, I will not give you. But then he said: (I would have done that) if I had not heard Allah's Messenger (may peace be upon him) say: He who takes an oath, but then finds something better than that, should do that which is better.