It's pretty easy for most people to read the Bible and get a sense for what “sheep” means without any help. They are simple, peaceful, trusting and willing to be led, and the image of the Lord as both a shepherd and a lamb reinforces a sense of innocence. And indeed, sheep represent people who desire what is good, to be good, and to do what is good. Arriving at such a state requires the work of a lifetime -- learning what's right, setting aside what's evil, determining to follow the Lord -- but once we arrive at such a state, we can be cared for by the Lord in peace.