What does Matthew 9:9 mean?

Tax collectors are rarely beloved, in any country, or any era of history. Jewish tax collectors in the time of Christ worked for the occupying Roman government, so they were especially hated in Israel. If that were not enough, tax collectors commonly took more than was required by the Romans in order to pay themselves. This meant tax collectors were frequently much wealthier than most Jewish citizens, who were just barely getting by day by day. The typical stereotype of a tax collector, in that time, was that of a greedy, sinful, traitorous sinner.

Matthew, the man referenced in this verse, is writing this book. He was a tax collector. He does not mention himself until well after several of the other disciples have been introduced. His writing is often arranged by topic, not time, so it's likely he was called by Christ before some of the other stories he's told so far in this gospel. Some scholars believe he was present at the Sermon on the Mount (Matthew 5:1–2), and possibly recording it word-for-word.

When Matthew does introduce himself, it is in the most low-key way possible. He describes Jesus walking by his tax booth and saying, simply, "Follow me." Matthew reports that he rose and followed Jesus. This may have taken place near Capernaum. Scholars suggest a tax booth may have been set up on the border there between two territories for the purpose of handling customs and excise taxes.

Matthew is sometimes called Levi in the books of Mark and Luke. Luke uses that name in describing this same moment, adding the detail that Levi left everything behind (Luke 5:27–28). Matthew and Mark both still list him as Matthew in various lists of disciples. It's unclear why Matthew/Levi was called by both names. One theory is that Matthew went by the name Levi, or was simply of the tribe of Levi, and was re-named by Jesus as Matthew upon his call.