He who took an oath and then found another thing better than (this) should expiate for the oath (broken) by him and do (the better thing).
Sahih Muslim Book 27, Hadith 19
← Previous Hadith A person sat late in the night with Allah's Apostle (ﷺ), and then came to his family and found that his children had gone to sleep. His wife brought food for him. but he took an oath that he would not eat because of his children (having gone to sleep without food) He then gave precedence (of breaking the vow and then expiating it) and ate the food He then came to Allah s Messenger (ﷺ) and made mention of that to him, whereupon Allah's Messenger (may peace he upon him) said: He who took an oath and (later on) found something better than that should do that, and expiate for (breaking) his vow.

Sahih Muslim Book 27, Hadith 18 Next Hadith → 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).

Sahih Muslim Book 27, Hadith 20