Musnad Abu Ya'la al-Mawsili 115:236

Amr ibn Muhammad al-Naqid narrated to us, Sulayman ibn Ubayd Allah al-Raqqi narrated to us, Ubayd Allah ibn Amr narrated to us, from Ma'mar, from Qatadah, from Anas, who said: The Messenger of Allah (may Allah bless him and grant him peace) forbade that a man should put on his sandals while standing.