“The tax collectors and the harlots will go into the kingdom of God before you.” (Matthew 21:31)

The author of the Gospel of Matthew was originally a tax collector; but he later became one of the twelve apostles.  Before following Jesus, Magdalena had led a sinful life.  However she later became the first witness to Christ's resurrection.  St. Paul was a foreigner who persecuted Christians before his conversion to Christianity; and St. Augustine, a great scholar of the early Church, was also rather rebellious in his youth.

As a result of acknowledging their sins, they became humble servants of Christ.

On the other hand, the Pharisees and priests were only concerned with the facade of the Law, and neglected to have a loving spirit for God and their neighbours.  Therefore Jesus described them as tombs that are beautiful on the outside, but corrupted on the inside.  Because they were self-centered, Jesus' teachings could not enter their hearts.
An old Chinese proverb says that everyone makes mistakes - the key is to recognize your mistakes and refrain from making them again.  This proverb and the spirit of this Gospel complement each other very well.