صحیح ابن حبان
Ibn Hibban
كتاب الأيمان
Book of Oaths
ذكر خبر ثان يصرح بأن الحالف مأمور بالكفارة عند تركه اليمين إذا رأى ذلك خيرا له من المضي فيه-
Another narration confirming that expiation is required when breaking an oath for something better
1 hadith
Hadith 4348
Sayyiduna Abdur Rahman bin Samurah رضي الله عنه narrates: The Prophet Muhammad صلى الله عليه وسلم said: "O Abdur Rahman! Do not ask for a government position, because if it is given to you as a result of your asking, you will be left to it (without divine help), but if it is given to you without your asking, you will be helped in it. And when you take an oath regarding something and later find that something else is better than it, then do what is better and offer expiation for your oath."