We came to the Messenger of Allah (ﷺ) when we were all young men of nearly equal age. We stayed with him for twenty days. He was extremely kind and considerate. He perceived that we missed our families so he asked us about those we left behind, and we informed him. Then he (ﷺ) said, "Go back to your families, stay with them, teach them (about Islam) and exhort them to do good. Perform such Salat (prayer) at such a time and such Salat at such a time. When the time for Salat is due, one of you should announce Adhan (call for prayer) and the oldest among you should lead Salat."

[Al-Bukhari and Muslim].

Al-Bukhari added in a version of his "And pray as you have seen me pray."