Musnad Ahmad 1153:58

Ibn Abi ‘Adi narrated to us, from Muhammad ibn Ishaq, who said: Nafi’ narrated to me—and his wife was an *umm walad* (a slave woman who bore a child to her master) of ‘Abdullah ibn ‘Umar, and she narrated to him—that ‘Abdullah ibn ‘Umar bought a slave woman on the road to Makkah, then he emancipated her and ordered her to perform Hajj with him. He sought two sandals for her but did not find them, so he cut two leather socks for her below the ankles. Ibn Ishaq said: I mentioned that to Ibn Shihab, and he said: Salim narrated to me that ‘Abdullah used to do that. Then Safiyyah bint Abi ‘Ubayd narrated to him that ‘Aishah narrated to her that the Messenger of Allah (peace and blessings of Allah be upon him) used to grant a concession to women regarding leather socks, so he ceased doing that.