To people accustomed to hear of God's holiness and the way He punishes sin, the parable of the Prodigal Son must have sounded improper. Yet Jesus gave this parable to describe how God loves the repentant sinner, although He hates sin.
With wonderful patience God respects the free-will of those who choose evil over good. He lets them experience the degradation to which their rebellion leads them. When they have learnt their lesson and return to Him, He welcomes them with love and joy, without any reproach at all.
The parable also tells us that there is a greater obstacle to conversion than the wild life of the young prodigal. The self-righteous Pharisees blamed Jesus for keeping company with tax-collectors and public sinners, and the parable was given in answer to their complaint.
The elder son in the story represents the legal-minded and judgemental Pharisee. He too needs to be converted to love and compassion but will not be, as long as he sees only what is wrong in others, and sees nothing wrong in himself.
Deliver me Lord, from the pride which condemns others for evils which exist in myself.