What does the Bible say about the elder brother in the prodigal son parable?

In the parable of the prodigal son, the elder brother embodies the attitudes of self-righteousness and jealousy, highlighting how the self-righteous fail to rejoice in the mercy and grace shown to others. He is angry upon the return of his wayward brother and feels that he deserves more favor from the father due to his own works, epitomizing the attitude of the Jewish leaders of Jesus' time who struggled to accept the grace extended to Gentiles. This response shows a deep misunderstanding of the nature of grace and forgiveness which should unite all sinners in joy over redemption.