It is narrated from Sayyiduna Uqbah bin Amir al-Juhani, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: "May Allah have mercy on the one who stands guard over the army."
Imam Darimi, may Allah have mercy on him, said: In the chain of this hadith, it is not established that Umar bin Abdul Aziz met Sayyiduna Uqbah bin Amir, may Allah be pleased with him.