A key can be used to open a door or a treasure chest.
But, once it is opened . . . where do we go from here? What gives anyone the blessings of God's kingdom?
prayer > Philippians 4:6-7 > because by praying the way God's word says to pray >
"the peace of God, which surpasses all understanding, will guard your hearts and minds through Christ Jesus."
obeying how our Father rules each of us in His own peace > Colossians 3:15
leading by example > 1 Peter 5:3, with 1 Timothy 3:1-10
our Father's correction > Hebrews 12:4-14
doing
"all things without complaining and disputing, that you may become blameless and harmless in the midst of a crooked and perverse generation" > in Philippians 2:13-16
These bring the good of God's kingdom. But, technically, these might not be the keys which Jesus first gave to Peter. After all, Peter did not become functional like he needed to become, even after getting the
"keys". He was not obeying God in His kingdom's peace, while he was denying Jesus three times, or discriminating against Gentile Christians > Galatians 2:11-13.
So, yes he got the
"keys", but he himself needed to use them so he could actually function in God's kingdom! I guess we could say that prayer, and obedience, and example leaders, and God's personal correction, and living without arguing and complaining so we live and love like Jesus could be considered part of our treasure we have in God's kingdom . . . now that those keys have opened this up for us.
So it's just a coincidence that Jesus and Peter are both called "rock"?
Well, Peter did not be and live like Jesus. So, I consider calling him "Rock" did not mean the same as calling Christ our Solid Rock or our Cornerstone. We have how Peter functioned as a
"hypocrite", even after he had gotten the Holy Spirit started with those Gentiles at the house of Cornelius, and Paul needed to stand up to Peter and stop that > Galatians 2:11-13.
So, I consider that Peter was not always exactly solid like Jesus; so possibly, after all, Jesus did not really mean Peter as being the rock on which Jesus would build the church. But I trust that after Paul corrected Peter, Peter then benefitted . . . learned from his error . . . and matured to become able to write his two epistles - - not only from inspiration, but from actual experience . . . after he had become qualified to call himself an elder.
Could it be that Jesus - the "Rock" and "cornerstone" of the Church - gave Simon the name "rock" because Jesus chose Simon to be his earthly representative and head of the Church after the Ascension? Could this be why Jesus gave "the keys of the kingdom of heaven" only to Peter (Matt 16:18)?
In case Jesus did not give keys to anyone else, we can see how Peter did not always represent Jesus very well. Plus, Peter himself noted how there were to be twelve apostles who would represent Jesus as witnesses to His resurrection > this is in Acts 1:15-26. So, I consider how those keys were meant for sharing his authority with others and making others also representatives.
And Peter did not go to Paul, in order to ordain Paul. But Jesus used Ananias who apparently was ready to understand Paul's calling. But Peter did not become ready to minister to Gentiles until the gift of Paul's apostleship was present in the church.
Oh yes, and now we have God's word, including all we have in Peter's epistles. But Peter is not the only representative whom God has used to give us His word . . . by the way. We have James, Jude, Paul, John, Matthew, Mark, Luke, and whoever wrote Hebrews if this was not Paul, and there are letters claiming to be from more than one person > for example 1 & 2 Thessalonians > from Paul and Sylvanus and Timothy.
So, I might say the keys have been used to get God's word started with us; and if anything would be a key to rightly receiving God's word, I would say that key is
"faith working through love" > as our Apostle Paul says in Galatians 5:6.
And it appears that at times there are ones both of Catholic and Protestant church culture who are not using
"faith working through love". So, each of us needs to be able to tell the difference, about who is telling us or doing what.
"Test all things; hold fast what is good." (1 Thessalonians 5:21)
With God, is it possible for each of us to be able to tell the difference. And God will guide us
"in one body" (Colossians 3:15) so that how He works in each of us (Philippians 2:13) will be in unity with all others who are obeying God in His own peace, and not depending on imperfect and even false leaders. However, yes there are both Catholic culture and Protestant culture people who are calling attention away from this. Beware of where your attention is being guided.