Abu Hurairah reported,
The Messenger of Allah ﷺ said, "By Allah, for one of you to persist stubbornly in an oath he has made concerning his family is more sinful before Allah than paying the expiation that Allah has prescribed." 
Ahmad 8208
Sahihوقال رسول الله ﷺ والله لأن يلج أحدكم بيمينه في أهله آثم له عند الله من أن يعطي كفارته التي فرض الله عز وجل
This is also sahih. It is in the individual Sahifah, numbered 95. Bukhari related it [8:128 printing/11:452–453 Fath] through the route of the Sahifah, along with the beginning of hadith number 1 from the Sahifah, as we noted there. Muslim related it [5:88 S/2:18 Bulaq] through the route of the Sahifah. Its meaning has already passed with a different wording, 7729, with the same chain of the Sahifah. We cited it there and noted this point.