Many Pharisees prided themselves in their strict avoidance of obvious, outward sin. But they refused to look inside themselves and acknowledge the presence of inner sin that didn’t fall within the boundaries of their man-made rules. Jesus knew that in spite of their obsession with outward perfection, they willfully resisted consciousness of their inner corruption and need for grace:

Woe to you, scribes and Pharisees, hypocrites! For you cleanse the outside of the cup and dish, but inside they are full of extortion and self-indulgence. Blind Pharisee, first cleanse the inside of the cup and dish, that the outside of them may be clean also. Woe to you, scribes and Pharisees, hypocrites! For you are like whitewashed tombs which indeed appear beautiful outwardly, but inside are full of dead men’s bones and all uncleanness. Even so you also outwardly appear righteous to men, but inside you are full of hypocrisy and lawlessness (Matthew 23:25-28 NKJV).

Jesus didn’t associate with “known sinners” like tax collectors because He minimized their sin ( Luke 19:1-10 ). He freely associated with them because He knew that they were more open to repentance.

Now it happened, as Jesus sat at the table in the house, that behold, many tax collectors and sinners came and sat down with Him and His disciples. And when the Pharisees saw it, they said to His disciples, “Why does your Teacher eat with tax collectors and sinners?” When Jesus heard that, He said to them, “Those who are well have no need of a physician, but those who are sick. “But go and learn what this means: ‘I desire mercy and not sacrifice.’ For I did not come to call the righteous, but sinners, to repentance” (Matthew 9:10-13 NKJV).

“Known sinners” weren’t full of self-righteous pride, deliberately concealing their hidden sins behind a legalistic façade of “righteousness.” Jesus was keenly ironic when He said, “I didn’t come to call the righteous to repentance.” He knew that the Pharisees weren’t righteous, but their pretense of righteousness kept them from accepting the only remedy for their condition — repentance and faith in Him. The obvious sins of “public sinners” made them more likely to repent and look to Jesus for the answers they needed.

We are all sinners, both inwardly and outwardly. Although we may not be notorious “public sinners,” we all share a fallen nature and are often controlled by the “flesh” — the “sin principle” — within us (Romans 8). Jesus’ stern warnings to the hypocritical Pharisees make it clear that sin we ignore and deny is no less serious in its effects than the sin of the public sinner.