The  biblical passage that makes reference to the “keys of the kingdom” is Matthew 16:19. Jesus had  asked His disciples who people thought He was. After responding with several of  the more popular opinions, Jesus aimed His question directly at His disciples.  Peter, responding for the twelve, acknowledged Jesus as the Christ, the Son of  the Living God. After this great confession, Jesus replied:

“Blessed  are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but  my Father who is in heaven. And I tell you, you are Peter, and on this rock I  will build my church, and the gates of hell shall not prevail against it. I will  give you the keys of the kingdom of heaven, and whatever you bind on earth shall  be bound in heaven, and whatever you loose on earth shall be loosed in heaven”  (Matthew  16:17-19).

Keys are used to lock or unlock doors. The specific doors  Jesus has in mind in this passage are the doors to the Kingdom  of Heaven. Jesus is laying the foundation of His church (Ephesians 2:20). The  disciples will be the leaders of this new institution called the church, and  Jesus is giving them the authority to either grant or bar access to the Kingdom.  The authority of the keys is to open and shut the doors to the Kingdom of  Heaven. Precisely how do the keys to the kingdom work? Biblically speaking, how  does one enter the Kingdom of Heaven?

Jesus tells us that unless one is  born again, he will not see the Kingdom of Heaven  (John 3:3). One is born again as  the Holy Spirit works through the Word of God to bring about new life in dead  sinners. So the faithful preaching of the gospel is one of the keys to the  kingdom. The other key is church discipline. In Matthew  18:15-20, Jesus gives us the guidelines for church discipline. He  specifically mentions in that passage the same “binding and loosing” language we  find in Matthew 16. Similarly, in 1  Corinthians 5:1-13, Paul urges the Corinthian church to ex-communicate the  man caught in adultery. Church discipline was considered by the Protestant  Reformers as one of the marks of a true church (along with the preaching of the  pure gospel and the administration of the sacraments).

Both of these  keys—the preaching of the gospel and church discipline—function in opening and  closing the doors to the Kingdom of Heaven. Through the preaching the gospel,  those who respond in faith and repentance are allowed access to the Kingdom of  Heaven; yet those who continue to harden their hearts and reject the gospel of  God’s saving grace are shut out of the Kingdom. Similarly, through church  discipline, the person who is caught in sin and remains unrepentant is barred  access to the means of grace—the Word, the sacraments and fellowship with the  community of believers. However, if the sinner repents, he or she can be allowed  back into church and given access to all the means of grace therein.

So,  the keys to the kingdom are the preaching of the gospel and the exercise of  church discipline. When these are rightly administered, i.e., in a biblical  church with duly appointed elders, access to the Kingdom of Heaven is ably  guarded. However, when the keys are not used correctly through obscuring the  message of the gospel or the lack of exercising church discipline, the results  are disastrous. Consider Jesus’ warning to the Pharisees: “But woe to you,  scribes and Pharisees, hypocrites! For you shut the kingdom of heaven in  people’s faces. For you neither enter yourselves nor allow those who would enter  to go in” (Matthew  23:13). If the gospel message is distorted or ignored, or if unrepentant sin  is not adequately disciplined, the doors to the Kingdom of Heaven are being shut  in people’s faces. When either of these two things occur, people in the church  are either believing in a false gospel or they have not truly repented of their  sin. In both cases the result is weeds growing in the wheat field of the church  (Matthew  13:24-30).