Sahih al-Bukhari 6384
In-book no 6384فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " وَاللَّهِ لأَنْ يَلِجَّ أَحَدُكُمْ بِيَمِينِهِ فِي أَهْلِهِ آثَمُ لَهُ عِنْدَ اللَّهِ مِنْ أَنْ يُعْطِيَ كَفَّارَتَهُ الَّتِي افْتَرَضَ اللَّهُ عَلَيْهِ ".
Allah's Messenger (ﷺ) also said: "By Allah, if anyone of you insists on fulfilling an oath by which he may harm his family, he commits a greater sin in Allah's sight than that of dissolving his oath and making expiation for it."