The “keys of the kingdom” open and close doors of spiritual opportunity (Matthew 16:13-20). Jesus referred to a “key” used by the Pharisees to lock knowledge away from ordinary people. More than likely a reference to “the tradition of the elders”.
The apostle Peter used a ‘key’ message on the Day of Pentecost to open the hearts of 3000 people! The “key” was not his application of Joel’s prophecy, which explained the Pentecostal phenomena that was taking place, but his inspired exposition of Psalm 16:8-11.
Jesus asked Peter, “Who do you say that I am?” The disciple’s reply was a revelation from the Holy Spirit. In response Jesus said, “Blessed are you, Simon…” We are not blessed when we repeat hearsay, or pass on the opinions of others, but when we speak revelation knowledge! (Jesus soon after rebuked Peter for speaking without revelation, and so potentially obstructive!)
Jesus contrasted Peter: “petros”: a pebble, with “petra”: a rock. It was not a comparison (as though Jesus was identifying Peter as The Rock) but a contrast! Jesus was saying, “Upon this rock of revelation knowledge from my Father in heaven — the knowledge that I am ‘the Christ, the Son of the Living God”, I will build my church.” As a man, Peter was certainly no rock! Galatians 2:11-14 makes this quite clear.
Knowledge is a key (Luke 11:52). Jesus has “the keys to Hell and Death”. He ‘opened’ the “gates” of Hell and Death when He rose from among the dead (Revelation 1:18). These “gates” shall not prevail against the church, because in rising from the dead our Lord unlocked them, leaving them open permanently! When Jesus opens or shuts a door, no one else can either open or shut it!
Expect, as you use the keys of the kingdom — words of revelation knowledge that open doors of spiritual opportunity — that God will bless you as He did Peter — the same God working in your own particular situation or circumstance!