Jesus compares Himself to a good shepherd. A shepherd knows his flock; he knows each of the sheep of his flock. He worries over each one, protecting each from wolf, starvation, wandering. If one wanders away from the others, then the shepherd seeks it out, brings it back into the fold.
Jesus says that He knows His own sheep, and His sheep know Him. We know His voice as He knows ours. Each of us is uniquely His. No one is like the other, but we are each specially and wonderfully made by Him. We are His possessions, for He created us.
Jesus tells us that just as the Father knows Him, and just as He knows His Father; so He knows us, and we know Him.
Like a good shepherd defending his sheep from wolf or lion, so Jesus defends us against our adversary, the wolf in sheep’s clothing or the lion who prowls about us, seeking one to devour.