Levi had a tax booth that stood between him and spiritual maturity and ministry. Our booths may be control over life, money, career, comfort, possessions, family, approval, success, earthly status, religion, or some negative things like poor character, bitterness, ego, and the things we are addicted to.
He had a choice to make. To grow, to go, to show the reality of his faith by a life of obedience and ministry.
Luke 5:28 says "left everything...and followed Him."
The implication is that you are not following Christ if you are still clinging to your sin and desire to control your life. You must repent and believe.
Beyond that, you aren't following Christ if this world is still your heaven, if your booth is between you and the mission that Jesus has for your life.
This is likely the moment when Levi became known as Matthew. The name carries an incredible meaning, "A Gift of God."