Most of us would rather be around people like ourselves. We feel most comfortable with those who look like us, think like us, talk like us, act like us, and more. We tend to avoid people who are different from us, especially if they have a questionable moral character.
So why would Jesus talk with Levi the tax collector (also called Matthew)? In that day, tax collectors were despised as traitors and thieves among their own people because they grew rich working for the Romans and their emperor. And as if talking to Levi wasn't enough, Jesus also ate at Levi's house with other tax collectors and sinners!
Didn't Jesus care about tainting himself by mingling with such people? He answered, "I have not come to call the righteous, but sinners."
The truth is, "sinners" refers to everyone: Jesus' self-righteous accusers, the others at Levi's house, and each one of us as well. Here we see Jesus' grace vividly extended to everyone around him, grace that transforms lives and changes the world. Only Jesus' saving grace can do that.
Only by Jesus' saving grace can we come into right fellowship with God. And once his grace touches our lives, we too should let it flow to those around us, including "tax collectors and sinners."