John: This is the parable of the Good Shepherd. The sheep/shepherd metaphor is rooted deeply in the OT. When David was called by God be king of Israel, what exactly was David doing? He was ending the sheep of his father Jesse. Later, during the Babylon Captivity, the image of the shepherd is one Ezekiel uses when prophesying against the faithless shepherds of Israel. The priests and ruling classes were the shepherds of Israel but most were unfaithful, thus Israel and Judah were led to worship false gods. See the First Commandment.
Gospel: John 10:1-18
New Testament: Acts 13:26-43