Musannaf Ibn Abi Shaybah

Hazrat Umar bin Umar bin Muhammad bin Hatib narrates that once a great leader from the non-Arabs came to meet Hazrat Umar. He inquired about Hazrat Umar and was informed that Hazrat Umar was outside Madinah. He set out to meet Hazrat Umar and met him while he was returning. That leader wanted to prostrate before Hazrat Umar, but Hazrat Umar said, "Raise your head for the One and Only Subduer."