It was prophesied he would come into the world, Abraham looked toward the day Christ would appear in the world, and Moses spoke of him, “God will send a prophet like unto myself from among your people, him you should hear” and in years to come Jesus would enter the world to fulfill his promise to Adam, Abraham, and Moses.
The nation of Israel was looking for a Messiah, but the Messiah they were looking for was one who would destroy their enemies and restore the kingdom of Israel. Therefore, when Christ came speaking of his death and resurrection, Peter stood up against him because the Messiah he seeks was to defend Israel not die for it.
Peter didn’t have it all wrong, Jesus will establish his kingdom on earth according to Isaiah, but before he establishes his kingdom, he must provide for the redemption of his friends, such as Abraham to whom he made the promise he would through his seed blessed the nations of the earth, and David to whom he promises an everlasting kingdom.
Peter had it wrong based on his motives, and his selfish acts, to which Jesus said, “If any man would come after me, let him deny himself, and take up his cross, and follow me.” Because he understood his disciples did not believe he was the Messiah, the Son of the living God, and were only with him because of the motives they had in mind which was to have Jesus restore the kingdom to Israel. Matthew 16:24.
But what the disciples of Jesus did not understand, was that Jesus was God in the flesh, he was not just a man, he was both man and God, and because they viewed him as just a man, they weren’t willing to accept him for who he was but for who they wanted him to be, their conquering Messiah.
Because of this, when it comes to driving out the demon that plagued the boy, they couldn’t drive him out, and when asked why they could not drive it out, Jesus told them it was because of their unbelief. The disciples did not believe Jesus was God, they did not believe he had the authority as God to ordained them to do such things, and because they did not accept Jesus for who he said he was their approach was without authority.
But after the resurrection, and the out pouring of the Holy Spirit on their lives, they were then able to see the kingdom of God in motion, understood who Jesus was and is, and began to have the faith they needed to have had to be able to bring forth fruit in honor of their king.
From this point on, Peter’s view was to die for the greater reward, no longer was he looking for a Messiah to destroy his enemies, but rather a Messiah whose kingdom is not just Israel, but the entire world. Peter’s mission was to declare the gospel of Jesus Christ throughout the entire world because he finally believed Jesus was not just a man, but God in human flesh saving the world.
Now that he understood Jesus was God, later John a disciple of Jesus would write concerning this matter. And he opened his message with these words, “In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made through him; and without him was not anything made that hath been made.”
The disciples were no longer saying with their mouth they believed Jesus is the “Son of the living God” Which is to say God, but with their lives proved they truly believed in Jesus by laying down their lives for the cause and enduring persecution in every place they went. Faith was now at work, they finally learned what it means to believe in Jesus because they were now able to see the kingdom of God.