I believe he is singing about the Prodigal son in the Bible. The story of how a son took his fathers inheritance and left home and spent it all on wild living until he had nothing left and was starving and a beggar. Finally when he was at his lowest he said even the slaves have it better than this, I will go home and beg my father to let me work for him. But his father is waiting with open arms waiting for his son's return, instead of being angry he throws the biggest celebration for him, puts robes on him and rings on his fingers. He said my son was lost but now he is found, was dead but now alive. The father is God and we are the son's and daughters who are lost and he is waiting for us to return with open arms. Jesus is the way the truth and the life.