"In the next picture he had left his good home and was minding a stranger's pigs in a foreign land"
The Prodigal Son working as a swineherd
Creative Commons Attribution Share AlikeThe Prodigal Son working as a swineherd - Credit: Jim Padgett

This refers to Jesus' parable of the Prodigal Son which appears in the Gospel of Luke in the Christian Bible (Luke 15:11-32). A parable is a story intended to teach a lesson or convey a message.

In the story of the Prodigal Son, a younger son takes his share of his father's money. He then leaves his father's home and wastes the money in extravagant living. As a result, he is forced to work as a swineherd (someone who looks after pigs). He then returns home. His elder brother is very angry with him, but his father forgives him and gives him a warm welcome.