Muhammad bin Ja'far bin Abi Kathir محمد بن جعفر بن أبي كثير · The Book on Clothing

"The Messenger of Allah (ﷺ) prohibited that a man should put on sandals while he is standing." This Hadith is Hasan Gharib. 'Ubaidullah bin 'Amr Ar-Raqqi reported this Hadith from Ma'mar, from Qatadah, from Anas. Both of the Ahadith are not correct according to the people of Hadith. Al-Harith bin Nabhan is not a Hafiz according to them, and we do not know any basis for the narration of Qatadah from Anas.