It is narrated from Sayyiduna Uqbah bin Amir (may Allah be pleased with him) that the sister of Uqbah vowed that she would walk to the House of Allah barefoot and with her head uncovered. The Messenger of Allah (peace and blessings be upon him) passed by her and said: "What is the matter with her?" The people said: "She has vowed that she will go to the House of Allah barefoot and with her head uncovered." The Messenger of Allah (peace and blessings be upon him) said: "Tell her to cover her head, ride, and perform Hajj."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14957