Ibn Shihāb reports:

ʿUmar went out to Shām (Greater Syria) and Abū ‘Ubaydah b. Al-Jarrāḥ was with us. They came to a ford while ʿUmar was on his camel. He dismounted his camel, took off his leather socks, placed them on his shoulder and took the reins of his camel and began to go down the ford. Abū ‘Ubaydah said, “O Leader of the Believers! You are doing this?! You take off your leather socks, put them on your shoulder, take your camel’s reins and go down the ford?! I wouldn’t want the people of this land to see you in such a state!” ʿUmar said, “If only someone else had said this o Abū ‘Ubaydah. You have made a lesson for the Ummah of Muḥammad – Allah’s peace and blessings be upon him! We were the lowliest of people but Allah gave us might and glory through Islam. If we seek glory through other than what Allah gave us glory through, He will abase us (again).”

In another version Abū ‘Ubaydah said:

O Leader of the Believers, should the armed forces and elite of Shām meet you in this condition? ʿUmar replied, “We are a people whom Allah gave might and glory to through Islam, so we will never seek glory through anything else.”

Reported by Al-Ḥākim, Al-Mustadrak Vol.1 pp61, 62. He declared it to be ṣaḥīḥ according to the criteria of Al-Bukhaārī and Muslim. Al-Dhahabī and Al-Albānī concur. See Al-Albānī, Al-Ṣaḥīḥah Vol.1 p50.