Mukhtasar Muslim

Narrated from Sayyiduna Abu Huraira (may Allah be pleased with him), he states that the Messenger of Allah (peace and blessings of Allah be upon him) said: By Allah! If any one of you insists on an oath regarding his family (which is harmful), it is a greater sin in the sight of Allah than that he breaks his oath and offers the expiation for it. (That is, instead of remaining firm on his oath, he should break it and offer the expiation for the oath.)