I will give you the keys of the kingdom of heaven; and whatever you bind (declare to be improper and unlawful) on earth must be what is already bound in heaven; and whatever you loose (declare lawful) on earth must be what is already loosed in heaven.
Since we are not only physical creatures but spiritual beings as well, we are able to stand in the physical realm and affect the spiritual realm. This is a very definite privilege and advantage. We can go into the spiritual realm through prayer and bring about action that will cause change in a situation. God is a Spirit… ( John 4:24), and every answer we need to every situation is with Him.
Jesus told Peter that He would give him the keys to the kingdom of heaven. All keys unlock doors, and I believe those keys (at least in part) can represent various types of prayer. Jesus went on to teach Peter about the power of binding and loosing, which operates on the same spiritual principle.
The power of binding and loosing is exercised in prayer. When you and I pray about deliverance from some bondage in our lives or in the life of another, we are, in effect, binding that problem and loosing an answer. The act of prayer binds evil and looses good.
Jesus has given us the power and authority to use the keys of the kingdom to bring to pass the will of God on earth.