YOU HAVE TO OPEN THE FRONT DOOR
In The Bible, there are Keys that God has or have been delegated to individuals that are very important. In 1 Chronicles 9:26-27 it speaks about men from the tribe of Levi who have been given the responsibility as gatekeepers of the house of God. As part of their duties, they had to guard the four entrances to the house (north, east, south and west) and possessed the key for entry.
In Isaiah 22:22, God gave Eliakim son of Hiliah special authority over Jerusalem. When Jerusalem was without a father-figure and leader, God raised Eliakim up for the task. God's words were heavy and profound because they would be heard again from God about His Christ - "I will place on his shoulder the key to the house of David; what he opens no one can shut, and what he shuts no one can open." As promised, you fast-forward to John on the Isle of Patmos and the Holy Spirit conveyed to John a communication about who now this key holder is - Christ Jesus - "To the angel of the church in Philadelphia write: These are the words of him who is holy and true, who holds the key of David. What he opens no one can shut, and what he shuts no one can open."
In Matthew 16:18-19, Jesus is speaking with Peter, however He is also speaking to all believers in Christ down through the ages who confess Him as Lord of their lives. Jesus said, "And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it. I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven." There is only One Rock (stable, immovable force) in the universe and He is Christ Jesus. He has the Keys of Heaven and because of our confession of faith in Him as Savior and Lord - He says to Peter, as well as to us, "I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven."
In Revelation 9:1 and 20:1 an angel has been granted The Key to The Abyss. The 9:1 passage is about opening The Abyss for creatures to come out. The 20:1 passage is about opening The Abyss for Satan to be locked in for a thousand years. Very important key. But one of the most crucial keys that The Lord Jesus Christ purchased for humanity with His death, burial and resurrection was The Keys of Death and Hades. Jesus says in Revelation 1:18, "I am the Living One; I was dead, and now look, I am alive for ever and ever! And I hold the keys of death and Hades." No more fear of death or Hades.
However, of all the Keys the Lord Jesus possesses, the one that seems the most important - He does not forcefully use. Jesus paid for The Key to Our Heart with His life, but He elects not to use it for the front door. He awaits acceptance of His invitation as you hear His knock on the door of your heart and hear His voice calling to your spirit. Jesus said, "Here I am! I stand at the door and knock. If anyone hears my voice and opens the door, I will come in and eat with that person, and they with me." - Revelation 3:20
God holds all the keys. He even has The Master Key for all the doors of your heart/life. He will unlock many a room inside your heart; He will open many a door in your life - but first You Have To Open The Front Door.