The Bible uses a key as a symbol of authority. In Isaiah 22:22, we see Eliakim the priest receiving "the key of the house of David…on his shoulder." A trusted servant to the king wore the key to the king's house on a hook on his shoulder. Therefore, he had the authority to open or close the king's house.
Revelation 3:7 uses similar symbolism, speaking plainly of Jesus having the key of David. In ancient Israel, the human king was in fact the steward of God, the true King of the land. Similarly, the divine Christ is the steward of His Father’s Kingdom. With that authority, only Jesus can allow or disallow someone entrance into the Kingdom—but no man had or has that authority.
Christ's statement in Matthew 16:19 and Matthew 18:18 show that His apostles had authority to represent Him, to teach as He taught them and to be instruments in helping people live the way of the Kingdom of God.
It is important to realize that the “rock” of Matthew 16:18 is Jesus, not Peter. Peter was a leading apostle of the early New Testament Church of God for many years, but not its chief cornerstone—that was and is Jesus Christ (Ephesians 2:20). Scripture calls Jesus “that Rock” in 1 Corinthians 10: 4. It is upon this rock—Jesus Christ—that our faith stands, Matthew 7:24-25.
With regard to Matthew 16:18, the words "thee" and "thou" in the King James Version are singular forms of the second person personal pronoun, "you." So, Jesus Christ was specifically referring to Peter in this passage. He was often the spokesman for the others and had a leading role in the early church. We must also note, however, that all the other disciples were in Jesus’ presence at that time (see verse 13).
In Matthew 18:18 the same command is given, but this time to all the apostles. Here, note that the second and third occurrences of the personal pronoun as shown in the King James Version is "ye" (the second person plural form of you), indicating that Christ is addressing more than one person—that is, all of His faithful apostles. So, not only was authority given to Peter (Matthew 16:19), great authority was indeed given to all these men. After they were converted they spread the true gospel to the entirety of the world.
Of course, it is erroneous to think any man could allow someone into the Kingdom of God whom God would not allow into it. Similarly, no man could disallow someone access to the Kingdom whom God would invite into it.
The Greek in Matthew 16:19 (as well as Matthew 18:18 and John 20:23) is not always clearly translated. These actions are called "future perfect passives" and can be rendered, "I will give you the keys of the kingdom of heaven; and whatever you bind on earth shall have been bound in heaven, and whatever you loose on earth shall have been loosed in heaven" (New American Standard Bible, Updated Edition). God is not obligated to bind an ungodly decision. In other words, Christ would lead the Church leadership to decisions that He had already bound in heaven, not vice versa.
Furthermore, in John 20:23 we read: “Whose soever sins ye remit, they are remitted unto them; and whose soever sins ye retain, they are retained” (KJV). This does not mean that men have the power to forgive sins. Only God and His son Jesus Christ have this power (Mark 2:7, 10). However, this verse states that Christ has given to the apostles and to all His ministers the authority to tell people that their sins have been forgiven by God. Please note the pronoun "ye" in this verse, which indicates that Christ is speaking to all of the apostles. Today, when ministers baptize and lay hands on people (Acts 2:38 and Acts 8:17), they can tell the repentant sinner that through the power of God and Jesus Christ, their sins have been forgiven. Man cannot forgive sins, but God can.
Anciently, when one came to seek the king's help or counsel, the servant's job was to open the door to the king's house and assist him in reaching the king. Christ's servants, the ministry, have a similar responsibility to assist those God is calling in coming to their King, Jesus Christ.
Christ showed that the religious teachers of His day, who had access to the knowledge of God's ways, had failed in this duty. "Woe to you lawyers! For you have taken away the key of knowledge. You did not enter in yourselves, and those who were entering in you hindered" (Luke 11:52). Occasionally, the ministry has the sad duty to inform some that because of their choices and actions, the doors to the kingdom are being closed to them unless they repent. See 1 Corinthians 5 or 2 Thessalonians 3:14.
Therefore, Christ's statements in Matthew 16:19 as well as in Matthew 18:18 show that His apostles had authority to represent Him, to teach as He taught them and to be instruments in helping people live the way of the Kingdom of God. Christ still lends His authority to His true ministers today to do the same work. Sadly, many falsely claim this authority and misuse it.
For more understanding, please read our booklet The Church Jesus Built.