مسند امام احمد بن حنبل · Hadith 1669

It was narrated that 'Abdullah bin 'Amir bin Rabee'ah said: 'Umar bin al-Khattab (RA) heard the voice of Ibn al- Mughtarif - or Ibn al-Gharif - the camel driver [one who urges camels on with his singing or chanting] in the middle of the night, when we were setting out for Makkah. 'Umar made his camel speed up until he joined the people, and found himself with 'Abdul Rahman. When dawn broke, 'Umar said: Now keep quiet, for dawn has broken; remember Allah. Then he saw 'Abdul Rahman wearing khuffain (leather slippers) and he said: Leather slippers?! He said: I wore them with someone whom was better than you, or with the Messenger of Allah (PBUH)). 'Umar said: i urge you to take them off, for I am afraid that the people will see you and follow your example.