Years ago, when our daughters were very young, we'd drop them off at our church's children's chapel on Sundays before the eleven o'clock service. One Sunday, the subject was the Twenty-third Psalm.
The minister told the children about sheep, that they weren't smart and needed lots of guidance, and that a shepherd's job was to stay close to the sheep, protect them from wild animals and keep them from wandering off and doing dumb things that would get them hurt or killed. He pointed to the little children in the room and said that they were the sheep and needed lots of guidance.
Then the minister put his hands out to the side, palms up in a dramatic gesture, and with raised eyebrows said to the children, "If you are the sheep, then who is the shepherd?"
He was expecting the kids to refer to him. A silence of a few seconds followed. Then a young visitor said,
" Jesus, Jesus is the shepherd."
The young minister, caught somewhat off-guard, said to the boy, "Well, then, and who am I?"
The little boy frowned thoughtfully and then said with a shrug, "I guess you must be a sheep dog."