Sahih Muslim · Hadith 4291
حدثنا محمد بن رافع، حدثنا عبد الرزاق، حدثنا معمر، عن همام بن منبه، قال هذا ما حدثنا ابو هريرة، عن رسول الله صلى الله عليه وسلم فذكر احاديث منها وقال رسول الله صلى الله عليه وسلم " والله لان يلج احدكم بيمينه في اهله اثم له عند الله من ان يعطي كفارته التي فرض الله
Hammam b. Munabbih reported:This is what Abu Huraira reported to us from Allah's Messenger (ﷺ), and he narrated a hadith and (one) of them is that Allah's Messenger (ﷺ) said: I swear by Allah, it is more sinful in Allah's sight for one of you to persist in an oath regarding his family than payment of its expiation which Allah has imposed upon him (for breaking the oath)