Since I love explaining this story...
A gate was a stronghold of a city. It was built nothing like the gates to castles and castle complexes like we see in the movies. It often was a labyrinth with many turns where there were parapets along the whole labyrinth before you got to the door as well so that a marauding army would attack anywhere but a gate.
Jesus was a bit of a different Schmeeka Rabbi (highest order of rabbi) than the other ones. He would often take trips (vacations) into Roman/Greek cities. Especially when a king would notice him (such as Herod did).
At the end of Jesus' ministry he took the Apostles to a city called Caesarea Philippi. This city was at the base of Mount Herman where one of the three springs that fed the Jordan River before it flowed into the Sea of Galilee.
This spring used to gush forth with such force that it was believed (by the Greeks) that the River Styx itself fed it. As a customary practice of placing a temple or idol at every water source the Romans built a temple to one of their gods here.
In the Roman world there were two main types of gods as described in our bibles. One was to Baal and the other to Ashera. Gods of Baal were ones of conflict resolution with favor resting on the one who made the more favorable sacrifice. (Blood sports) It wasn't simulated violence it was the real thing...It was believed that successful sacrifice to one of these would allow you to win your case in court, that pesky neighbor would lose and have to move or some other such thing.
There there were the Ashera gods...these were fertility gods. They would grant you children, good crops and wealth. This sort of god was appeased through sexual activity of some kind.
At Caesarea Phillipi there was a temple to the fertility god Pan. He was a half goat and half man creation. Customarily they would bring out the goats and get them to start mating and then the dancing girls would come out and dance suggestively....then it was audience participation time. And it was known to be the world's largest outdoor orgy.
For Jesus to bring the disciples there it would be rather disconcerting. These guys were just men...not raised in the Temple or as Levites...they probably had cracked jokes about the place in the past with other guys. Now....at the end of three years of following a Rabbi it was shameful and hideous to look upon all those naked bodies going at it. Contempt for such sin would be an understatement.
This is the exact place (on a nearby hillside with the "party" going on as a backdrop) where Jesus begins a lesson for the 12.
Who do people say that I am?
Peter answered with the names of three former prophets who were known for their outrageous zeal for God....otherwise known as passionate men.
All of these guys had one message about God and they were bent on delivering that message no matter what the personal cost in friendships or their lives.
(Jesus obviously mirrored these guys in passion...or maybe these prophets merely mirrored Jesus. )
Who do you say that I am?
Peter says what we expect him to say...that Jesus is the Messiah who is God himself...Emmanuel/God with us.
But not only that...all of Jesus' attributes as well...that God is so very good and kind....even to some of who we think is the least godly among us.
BUT...that was kind of a "no brainer" by this point. They had seen Jesus walk on water, heal the sick, give sight to the blind, heal a blind, deaf-mute man (the ultimate test for a genuine miracle of God according to the Jews (Matt 12) and feed thousands out of just a pocketful of food.
The biggest thing is that this is going on with that orgy going on in the background. Not one word of condemnation is being said about it....
the big IN OTHER WORDS
The telling how good Jesus/God really is... and that He wants us to have a personal relationship with him is what his "Church" or Ekklesia (lit: called out ones) is really built upon.
AND HERE'S WHATS MORE:
That when this is really embraced as your strongest thing that we ALL (the "you" in "I will give you the key" is plural) have the Keys to the treasure rooms of all the power, might, and wealth that Heaven has at it's disposal to further God's kingdom. (a limitless supply)
And all of that filth of self indulgence, self importance at the expense of others, all that shameful knowledge of pleasure cannot stand up to the message that Jesus/Emmanuel (and all that He stands for) loves us in spite of our shameful ways. This stronghold and most fortified center of all that filth and ungodliness can't stand up to this message...the GOSPEL/Good News message.
Yes, when Paul writes: "Therefore (because of all the stuff he said before) there is now NO CONDEMNATION for those of us in Christ Jesus." it is kinda an understatement...