Musannaf Ibn Abi Shayba 33:874

Al-Fadl ibn Dukayn narrated to us, he said: Abu Isra’il mentioned Umar ibn Abd al-Aziz and said: Ali ibn Badhima narrated to me, he said: I saw him in Medina, and he was the best of people in clothing, the most pleasant of people in scent, and the most arrogant of people in his gait—or the most affected of people in his gait. Then I saw him afterwards walking with the gait of the monks. So whoever tells you that a gait is an innate disposition, do not believe him after Umar ibn Abd al-Aziz.