NOTES for Luk 5:27-32
The Pharisees who came to listen to the Nazarene Teacher and intellectually discuss "the divine" with Him are completely unable to bear the fact that He sits down to eat with tax collectors, whom they hardly even consider people. They grumble because they think that if He really is the Messiah (or even simply God's messenger), then He ought to reward righteousness. What they mean is that He should exalt them, the champions of righteousness. But the Word of God calls the Messiah the Savior and Redeemer of Israel. From what slavery is a righteous person to be redeemed, and from what is he to be saved?
The Lord replies that He came to call not the righteous, but sinners to repentance. To acknowledge oneself as needing salvation - that is exactly what is necessary in order to become a participant in that salvation. A sinner needing repentance. A slave of sin needing redemption. A sick person needing a physician. This is exactly what the Pharisees will not accept, and so they begin to nitpick at Christ, asking why, then, His disciples, the supposedly called sinners, do not fast and do not make progress in other ascetic exercises.
To acknowledge oneself as poor, as needing Jesus, is the most important turning point not only for the Pharisees, but for any person. "Only acknowledge your guilt", the Lord says through Jeremiah the prophet (Jer 3:14).