It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) forbade walking with a shoe or sock on only one foot. Abdullah, the son of Imam Ahmad (may Allah have mercy on him), says that my father (may Allah have mercy on him) did not narrate this hadith to us, but had only recorded it in his draft. I think he abandoned this hadith because of Amr bin Khalid, who narrates it from Zaid bin Ali, and Amr bin Khalid has no standing.
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 2948
Hadith Gradingحکم دارالسلام:إسناده ضعيف جدا، الحسن بن ذكوان ضعيف، ويغني عنه حديث أبى هريرة الذى سيأتي فى المسند : 245/2