John 10:11-18 is part of a longer discourse in which Jesus tells his disciples and us that he is the way to heaven and eternal life. In this passage he explains this concept by comparing himself to a shepherd. The image of a shepherd was one that was common among members of his audience. Palestine was more of a pastoral region than an agricultural region, so shepherds were very common. Sheep are quite dumb. They will follow anyone who leads them, even if it means that they will be led astray. A good shepherd watches out for his flock and protects them even to the point of sacrificing himself.