Why did the older-brother/Pharisees not see their need despite being under the covenant promises?
The older brother pictures Israel’s Pharisees, who were under the covenant promises but were so self-righteous and filled with their own importance that they saw no need of anything. Their pomp and self-righteous mentality kept them from recognizing their need, and they became angry at believers embracing Christ as Messiah.
Les explains that the older brother is typical of the Pharisees in Israel. Though they had been under the covenant promises just like the other brother, they were so self-righteous, so filled with their own importance, pomp, and circumstance, that they did not see need of anything. When they saw the little element of believers embracing Christ as the Messiah, it made them angry. Like Saul of Tarsus, they thought they could stamp them out by putting them to death and in prison. That is the mentality of the other brother: self-righteous. Jesus said the well person does not need a physician; the sick person does. Paul makes it plain that no one can be saved or enter salvation while thinking they can make it on their own; one must come as a sinner, and that is mandatory.