Why did Jesus say to Peter ‘Get Behind Me Satan?’ Could it not have been that Peter was simply being protective of Jesus?
Yes and no.
At that stage, although the disciples had travelled with Jesus throughout His ministry, up until this point, they did not understand His purpose. The disciples were Jewish and had the Jewish expectation of the Messiah. You can read various views on this subject here – https://en.wikipedia.org/wiki/Messiah_in_Judaism
However, bear in mind the Talmud was not begun to be written until the 2nd century, AD and completed in the 5th century, AD.
The expected Messiah
At the time of Christ, the Jewish people expected the Messiah to be born of the line of David and drive the Romans out of Israel.
Basically, they expected a warrior king.
Jesus knew the reason He had been born. So, at the time He said this to Peter, He was beginning to prepare them for what lay ahead. His capture, suffering and crucifixion. Perhaps they only saw all His good works… the healings, the deliverances from demon possession and the miracles He performed.
This was not Jesus’ purpose. These were signs of Who He was.
The Spirit of the Lord is on Me, because He has anointed Me to preach good news to the poor. He has sent Me to proclaim deliverance to the captives and recovery of sight to the blind, to release the oppressed, to proclaim the year of the Lord’s favor.” Then He rolled up the scroll, returned it to the attendant, and sat down. The eyes of everyone in the synagogue were fixed on Him.
Luke 4: 18-20 Berean Study Bible.
This was when His ministry commenced. Since then He had been training His disciples and now He needed to warn them.
He disappointed that He had to say it?
“And having turned, He said to Peter, “Get behind Me, Satan! You are a stumbling block to Me. For your thoughts are not of the things of God, but the things of men.”
Matt 16:23 Berean Literal Bible
Why Did Jesus say get behind me Satan?
The clue is in “For your thoughts are not of the things of God, but the things of men.”
Yes, Jesus was a servant-King, but His purpose was not simply for that generation. He had come to die for the sin of mankind.
Was Jesus beginning to be apprehensive? Possibly. Therefore, He needed His mind fixed on His main purpose, and to look ahead. He did not need one of the leading disciples to try to distract Him from that purpose.
There is a lot more to the story, most people know that, but this morning that phrase ‘jumped out’ at me.