Reference: Safahaat Mushriqah min Hayaat al-Imaam Muhammed ibn Saalih al-‘Uthaymeen – Page 154-155
Ayman ibn ‘Abdir-Rahmaan Abaanamee narrates:
Once he went to give a lecture to the National Guard where senior officers were waiting to welcome him to the masjid. So when he arrived, he took his shoes off inside the car and got out; His companion turned to him and suggested he put them on [again] for appearances sake [since he was meeting senior officers of the National Guard]. So the Shaykh said to him: No, leave them. So he continued [to proceed] barefoot, and that only increased him in respect and honour.