Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) sent us in a detachment. They met the enemy and the people fled. We came to Madinah, opened its gate, and said: O Messenger of Allah (peace and blessings be upon him), we are the ones who fled. He (peace and blessings be upon him) said: "Rather, you are the ones who turn back to fight, and I am your group."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18082