Musannaf Ibn Abi Shaybah

Salim bin Abdullah narrates that Umar bin Abdul Aziz (may Allah have mercy on him) said to me, "Write and send to me the method of Hazrat Umar (may Allah be pleased with him)." I said, "If you act in the same way as Hazrat Umar did, then you will be considered superior to Hazrat Umar, because neither is your era like the era of Hazrat Umar, nor are the people with you like the companions of Hazrat Umar."