What does Matthew 9:12 mean?

Jesus has called Matthew to follow Him as one of His core twelve disciples (Matthew 9:9). Matthew was a tax collector, one of the most despised people in Israel. Tax collectors were Jewish men who took money from other Israelites and gave most of it to the occupying Romans. The remainder they could keep, as allowed by Roman order, as payment for their services. Most Jewish people saw tax collectors as greedy traitors. It would have been scandalous, in that culture, for a righteous man like Jesus to invite a tax collector to become His disciple.

Worse, Matthew then hosted a dinner party at his home with his friends (Matthew 9:10). These, of course, were other tax collectors and "sinners." As used in these passages, "sinners" are those people unwelcome in religious society because they did not follow the rules of the Pharisees or, in some cases, the law itself. That's not to say they were innocent of sin—their actions were certainly immoral—but these people were overtly identified by their sins in that culture.

The Pharisees make baffled accusations, asking Jesus' disciples why He eats with these people, something they would never do (Matthew 9:11). Now Jesus answers them in a way that both explains His actions and exposes the Pharisees.

Healthy people don't need a doctor, Jesus says. Sick people do. Jesus was not declaring the Pharisees to be healthy, but pointing out that they saw themselves that way. Jesus told them He was there to help people who knew they were sick. Spiritually speaking, they understood they needed help. They were open to the truth: that they needed saving.

Two important applications emerge from this statement. First, the purpose of good works and evangelism is to reach the lost (Matthew 5:11–16). Christians are not called on to barricade themselves away from anyone they see as a "sinner." Of course, it's important to guard friendships and associations (Psalm 1:1; 1 Corinthians 15:33). However, believers cannot live out the love of Christ while avoiding all possible contact with lost people (1 Corinthians 5:9–10). Self-labelled Christians, or churches, who turn their noses up at sinners are like doctors, or hospitals, who refuse to associate with sick people.

Second, Jesus was not condoning the wrong choices of the people He spent time with. Showing love and kindness does not require—and does not imply—endorsing everything the other person does or believes. Christ was introducing them to Himself as the only way to be forgiven and redeemed. He was showing them the true face of God, full of love and compassion for them.