Musnad Ahmad 129:0

Narrated Malik ibn al-Huwayrith: We came to the Prophet (ﷺ) while we were young men of similar age. We stayed with him for twenty nights. The Prophet (ﷺ) was merciful and kind. He thought that we missed our families, so he asked us about those we left behind of our families. We told him, and he said: "Return to your families, stay among them, teach them, and command them." He mentioned things, some of which I remember and some I do not. He said: "Pray as you have seen me praying. When the time for prayer arrives, let one of you call the Adhan for you, and let the eldest of you lead you in prayer."