Swearing not to go shopping with his family and then going in order to obey his father

Q: I performed Hajj - all praise be to Allah - with my father and my family this year, 1409 A.H. During the Hajj, specifically on the day we moved from Muzdalifah and before we stoned Jamarat-ul-‘Aqabah (the closest stone pillar to Makkah), my father and aunt said that they wanted to buy some clothes as gifts. I said, "Did we come to perform Hajj or buy clothes?" They said that of course we had come for Hajj. So I said, "If we want a full reward we should do so by remembering Allah, saying Tasbih (glorification of Allah) and asking for His Forgiveness, and not waste time in going shopping and whatever else we may do." (Part No. 23; Page No. 106) My father then suggested that we should wait until after we had performed Tawaf-ul-Ifadah (final obligatory circumambulation around the Ka‘bah in Hajj) and then we could go shopping. I swore by Allah that as they performed Hajj with me, I would not go shopping. My father argued that the wives of the Sahabah (Companions of the Prophet) used to go for walks with their husbands during military campaigns and do others things. I told them that it was not permissible for women to walk around the markets, and for them to talk to the salesmen and uncover their faces to see the merchandise that they want to buy. Is this permissible, bearing in mind that this was the first time for these women to enter the markets? Can the oath I took, of not going to the market with them, then my breaking the oath and my going to the market so as to avoid upsetting my father and aunt, be expiated? Please advise us and may Allah show you mercy!

A: It is obligatory on you to offer Kaffarah (expiation) for breaking your oath, and the Kaffarah is to free a believing slave or feed or clothe ten poor people. If you are unable to do this, you should observe Sawm (Fast) for three days.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.