‘Uthman b. Abul ‘As said that the last command God’s messenger gave him was, “When you act as imam for people, make the prayer short." Muslim transmitted it.
In a version by him it says that God's messenger said to him, “Act as imam for your people” to which he said he replied, “Messenger of God, I find a defect in myself.” Telling him to come near and making him sit down in front of him, he placed his hand on his breast between his nipples; then telling him to turn round, he placed it on his back between his shoulders. He then said, “Act as imam for your people. Whoever acts as imam for people must be brief, for among them are the aged, among them are the sick, among them are the weak, and among them are people who have business to do. But when any of you prays alone he may pray as he likes.”
We used to pray behind the Prophet, and when he said, "God listens to him who praises Him," none of us bowed his back till the Prophet placed his forehead on the ground.
Abu Huraira reported God’s Messenger as saying, “They lead you in prayer, and if they do it properly you will reap a reward, but if they make mistakes you will reap a reward and they will be held responsible.
