This entire 16th Chapter of the Book of Matthew is focused on the need of Spiritual Discernment. The Pharisees and Sadducees didn't have it, at this point Jesus' own disciples didn't know when to use it, we see that those who thought that Jesus was John the Baptist, Elijah, Jeremiah or one of the other Prophets didn't have it. It wasn't until Jesus asked Simon Peter who he thought He was, the Spiritual Discernment was used.
"You are the Christ, the Son of the living God." Jesus lets Peter know right then and there that he had it, because without it, he would not have known who He truly was.
We see this still today, many different groups of people who say that they are the true Christians, but don't have the revelation of who Jesus truly is. You see, the Pharisees and Sadducees knew scriptures and laws, but had not the discernment of who Jesus truly was/is. Yet they continue to teach false doctrine.
The rock that Jesus has built His church on is "the rock" or the foundation of Spiritual Discernment. Discernment/Revelation of who Jesus is while He lets us know who we are in return. That's "the rock". The church is made up of those who have been born again and no longer operate in the flesh but the spirit.And this is what the "the gates of Hades shall not prevail against", Spiritual Discernment.
"Get behind Me, Satan! You are an OFFENSE to Me, for you are not mindful of the things of God, but the things of men."
Peter at this point in time was not using Spiritual Discernment . Peter, earlier acknowledged Jesus as the Christ, the Messiah, the Savior forgot all about that after hearing Jesus speak of His death, which drew out that rebuke from Jesus. Being "mindful of the things of man and not of God", gets us all of course and causes us to say, see and hear things that are out of the will of God. And subsequently, we get rebuked.
***If you are going to "take offense" to anything, let it be because someone or something is trying to prevent you from fulfilling your God-given purpose.
"If anyone desires to come after Me, let him deny himself, and take up his cross, and follow Me."
I imagine He was looking at Peter when He spoke these words. I can hear the frustration in His voice even now. In other words, what Jesus was saying and is still saying is this, 'if you desire to come after Me, set your mind on the things of God and not man. You are going to need Spiritual Discernment every step of the way. Tap in to it, it's available'.
That's my journey through the 16th Chapter of Matthew.