The Messenger of Allah ﷺ said, "None of you should walk in a single sandal. Either wear them both or take them both off."
حدثنا عبد الله بن مسلمة عن مالك عن أبي الزناد عن الأعرج
أن رسول الله ﷺ قال لا يمشي أحدكم في النعل الواحدة لينتعلهما جميعا أو ليخلعهما جميعا
Bukhari narrated it in the Book of Clothing, chapter "One should not walk in a single sandal," hadith 5855, from Abdullah bin Maslama Qanabi. And Muslim narrated it in the Book of Clothing, chapter on the recommendation of putting on the right sandal first, etc., hadith 2097, from the hadith of Malik through the same chain, and it is found in the Muwatta (Yahya's version) 2/916.