How can a person enter salvation?

Les explains that the older brother in the account represents the self-righteous Pharisees in Israel. Though they were under the covenant promises, they were so filled with their own importance and self-righteousness that they saw no need of anything. When they saw believers embracing Christ as the Messiah, it made them angry, and like Saul of Tarsus they thought they could stamp them out. But Jesus Himself said the well person does not need a physician; the sick person does. Paul makes it plain that you cannot enter salvation if you think you will make it on your own; you must come as a sinner, which is mandatory.