When what we say lifts Jesus as God and acknowledges ourselves as servants then we have the keys of Kingdom. When speaking in independence we lose them. Spiritual authority is based on submission to Jesus, ‘Son of the living God.’
In Matthew 16 following Peter’s confession:
16 …, ‘You are the Messiah, the Son of the living God.’
19 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.’
It seems Jesus gave Peter Carte Blanche; whatever he says goes. So, many believers pray believing they will get what is asked with an authoritative voice. However Peter immediately uses this authority and is rebuffed –
23 … ‘Get behind me, Satan! You are a stumbling-block to me; you do not have in mind the concerns of God, but merely human concerns.’
Isaiah 33:5-6 coming from a different angle illuminates –
The Lord is exalted, for he dwells on high; … He will be the sure foundation for your times, a rich store of salvation and wisdom and knowledge; the fear of the Lord is the key to this treasure.
Isaiah lifts up the Lord, as Peter has, great things are promised on the basis of the fear of the Lord. If I put this thinking into Matthew 16 I see Jesus saying, while you acknowledge Me as God and take Me seriously, then you have the keys of the kingdom.
For the complete study – Key to the Kingdom