The prohibition of persisting in an oath that will harm the family of the one who swears it, so long as not persisting in it does not involve anything unlawful

Hammam b. Munabbih reported: This is what Abu Huraira reported to us from Messenger of Allah ﷺ, and he narrated a hadith and (one) of them is that Messenger of Allah 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).

حَدَّثَنَا مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، حَدَّثَنَا مَعْمَرٌ، عَنْ هَمَّامِ بْنِ مُنَبِّهٍ، قَالَ هَذَا مَا حَدَّثَنَا أَبُو هُرَيْرَةَ، عَنْ رَسُولِ اللَّهِ ﷺ فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ رَسُولُ اللَّهِ ﷺ " وَاللَّهِ لأَنْ يَلَجَّ أَحَدُكُمْ بِيَمِينِهِ فِي أَهْلِهِ آثَمُ لَهُ عِنْدَ اللَّهِ مِنْ أَنْ يُعْطِيَ كَفَّارَتَهُ الَّتِي فَرَضَ اللَّهُ " .