Mark 2:15-17 NIV
[15] “While Jesus was having dinner at Levi’s house, many tax collectors and sinners were eating with him and his disciples, for there were many who followed him. [16] When the teachers of the law who were Pharisees saw him eating with the sinners and tax collectors, they asked his disciples: “Why does he eat with tax collectors and sinners?” [17] On hearing this, Jesus said to them, “It is not the healthy who need a doctor, but the sick. I have not come to call the righteous, but sinners.”

Strange, isn’t it, that the religious leaders just couldn’t leave Jesus alone. Wherever He was, whatever He did, they were there, on His case, picking on Him for daring to challenge not only their authority but also their very philosophy of life.

The difference between the Pharisees and Jesus was simple.They focused on the “don’ts” while Jesus focused on the “do’s”. What do I mean? For the Pharisees, their preoccupation with being “holy” meant that they were careful not to do anything that they believed would displease God.

God’s laws were protected by a multiplicity of additional laws and prohibitions added by the learned rabbis over years of study, and preserved in the Mishnah.

Google explains…

“The Mishnah is a third-century Jewish collection that expands upon the legal material and language of the Old Testament and is considered to be “oral Torah.” Mishnah (the Hebrew term מִשְׁנָה means “study by repetition”) is the foundation of all subsequent Jewish law and praxis, from the Talmuds up to modern-day Jewish literature.”

To the Jewish religious leaders, the Mishnah was as authoritative as the Tanach. They were incensed when Jesus did what they considered to be violations of these additional laws, and they were quick to pick on Him for every infraction.

Jesus had chosen Matthew to be one of His disciples, a despised tax collector who worked for the Roman government. Matthew had arranged a dinner to which he invited Jesus and his circle of friends, outcasts like himself, of course. The Pharisees, nosing around as usual, noticed this event and immediately lodged their objection. “Why does Jesus share a meal with the riff-raff?”

On this occasion, Jesus dared to fellowship with those whom the Pharisees considered to be undesirable people, the outcasts of society, “sinners” in their eyes since these people didn’t care about “the law”.

In Hebrew culture, sharing a meal with people was much more than that. There was significance in eating together. It was a declaration that the participants were at peace with each other, no issues, no animosity.

How could Jesus be at peace with these “sinners” if He was who He claimed to be, the Son of God? In any case, He was a recognised rabbi, and rabbis don’t eat with sinners.

As usual, Jesus declared His intention not to condemn people for their sinfulness but to rescue them from self-destruction and call them into fellowship with Him.

Mark 2:17 NIV
[17] “On hearing this, Jesus said to them, “It is not the healthy who need a doctor, but the sick. I have not come to call the righteous, but sinners.”

Jesus had declared His intention not to do away with God’s law, but to fulfill it in the way that God meant it to be lived, not by being hypocritically holy but by treating all people with kindness and compassion.

Matthew 5:17-18 NLT
[17] “Don’t misunderstand why I have come. I did not come to abolish the law of Moses or the writings of the prophets. No, I came to accomplish their purpose. [18] I tell you the truth, until heaven and earth disappear, not even the smallest detail of God’s law will disappear until its purpose is achieved.”

Since God’s word is eternal, what He intended in His law (instructions), was meant to be understood in the context of His nature and attributes, not according to human opinions and interpretations.

Jesus declared His purpose in His words to Nicodemus…

John 3:17 NLT
[17] “God sent his Son into the world not to judge the world, but to save the world through him.”

Once again, by their picky irritation with Jesus, the Pharisees revealed the nature of their hearts, self-serving and, by contrast, the nature of the heart of Jesus, selflessly serving.