 He doesn't realize he could get up on the side of a mountain. He could slip. He could fall to the rocks below. So the good shepherd goes out and pursues him. It might take him several hours, but he goes and finds him, puts him over his shoulders. Have you ever seen those paintings of Jesus with the sheep? Little sheep around his neck. He'll walk him back to the flock. Several nights later, he counts the flock, and that little sheep once again is gone. He's got to leave the other sheep.