24th Sunday in Ordinary Time: The Prodigal Son: Which Brother are We?

In today's Gospel, Jesus responds to the Pharisee's accusation that he is too chummy with tax collectors and sinners by giving the moving parable of the Prodigal Son. In it two sons are juxtaposed -- one son's sins against his father are public and obvious (similar to the tax collectors and sinners) and one son's sins of the heart are more hidden but no less serious (like the Pharisees and scribes). What is the similarity and what is the difference between the two son? Both sons are sinners, and only one son repents. Which son will we be?