You may have noticed that of all the gospel writers, Luke is the one who tends to pay attention to the details, and this story is a classic example. Zacchaeus is a tax collector. Most gospels might stop there, but Luke tells us that he's the head honcho of tax collectors, and he's rich, and that he's short.

Good Jews just didn't associate with tax collectors and despised them for several good reasons:

They worked for the Roman oppressors by essentially buying up contracts for tax collection and then skimming off their profits from the top.

Associating with them made Jews ceremonially unclean, and therefore unfit to enter a synagogue or participate in the great temple festivals.

In the pursuit of tax money they were known as brutal and selfish people, finagling every penny they could from the poor and demanding big profits from the rich.

Once again a large crowd follows Jesus, offering a chance for the well-known chief tax collector to get a look at this man who was becoming a sensation. But Zacchaeus couldn't get a good look at him because he was so short. So, risking ridicule and even violence, Zacchaeus climbed a tree to get a look.

Was it mere curiosity? No, something about Jesus had struck a deep chord in Zacchaeus's heart. Perhaps he was profoundly unhappy and lonely. Perhaps he had heard that Jesus had talked to other tax collectors and even accepted dinner invitations to their homes. It must have been hard for Zacchaeus to endure such hatred and ridicule, no matter how rich he had become.

As Jesus passes by, Zacchaeus sits perched in a tree. He doesn't dare to do or say anything. Then Jesus stops right there under that tree, looks up at Zacchaeus, whose heart must have been pounding, and says something unimaginable. Jesus invites himself over to Zacchaeus's house for dinner---no, he demands it! "Zacchaeus, come down immediately. I must stay at your house today." The crowd mutters about Jesus' bad behavior as Jesus and his disciples head off to Zacchaeus's house for dinner.

I imagine the scene unfolding like this: in the middle of the dinner, Zacchaeus stands up, as if to offer a toast. Instead he makes a vow: "Here and now I give half my possessions to the poor, and if I have cheated anybody out of anything, I will pay back four times the amount." It's interesting that Zacchaeus doesn't stop being a tax collector (somebody's got to do it, after all), but he commits himself to doing it honestly.

Jesus honors him by declaring, "Today salvation has come to this house, because this man, too, is a son of Abraham. For the Son of Man came to seek and to save what was lost" (vv. 9-10). In the face of rejection by his fellow Jews, who put him outside the covenant, Jesus declares Zacchaeus to be one of them, a fellow heir of God's covenant with Abraham.

Notice that Zacchaeus's salvation involves two things: he believes in Jesus, and he does the right thing by turning away from his cheating practices. He commits himself to right belief and right living at the same time. Salvation is a change of heart and a change of life.