Where is the Cross in The Prodigal Son Parable?
Jesus, through The Prodigal Son parable, explains in part why he needed to die on the cross. Dr. Ken Bailey, who lived and taught in the Middle East for over 40 years, writes, “The father’s suffering at the beginning of the story has no effect on the prodigal son. The son isn't even aware of it. The son must first witness a demonstration of the father's suffering. WITHOUT WITNESSING this demonstration, the callous son will NEVER understand that he is the cause of the broken relationship. Without the father's visible 
demonstration of suffering, the prodigal will return to the house as a servant. He will—quite likely—take on more and more of the characteristics of his older brother. Without this visible demonstration of costly love, there can be no reconciliation. Isn’t this the story of the way God deals with the sin of the world on the cross?”
Cross or Shepherd?
Jesus told The Lost Sheep, The Lost Coin, and The Lost Sons (Prodigal) as one, inter-related parable. Interestingly, the early church didn’t use the symbol of the cross for Christianity but instead used, among other things, the image of a joyful shepherd carrying the sheep back to its fold. See The lost sheep.
For some, it's difficult to see how Jesus' death on the cross saves. In fact, some see God as brutal BECAUSE of the cross. For these, the Good Shepherd image may more clearly show the heart of God and better explain the need for the cross—a picture that weds both a good and joyful shepherd (God) and a previously terrified sheep (us) WRAPPED around his shoulders as he JOYFULLY goes about his mission of restoring his sheep.