The Creator of the world (John 1:1-3) had just been arrested, but it was in a place and at a time that was His own choice. God was in control; it was prophesied centuries before. But the disciples did not understand. Peter, who had declared his intention to die with Jesus if necessary (a foolish statement made more with bravado than true courage) had a sword; one of two that they took with them (Luke 22:38).
 
With his Master captured, Peter got out his sword and swung it at the head of Malchus (John 18:10), the High Priest's servant. Presumably he had intended a fatal injury but he missed, and only cut off his ear. Jesus was not impressed or grateful. Instead Peter's action earned a stern rebuke. The arrogant fisherman thought he could protect Jesus! He did not know his own weakness; nor did he know the power of Jesus or His authority to ask for innumerable angels to protect Him. Amazingly Jesus fully healed the ear (Luke 22:51) and later re-commissioned the repentant Peter (John 21:15-17).
 
The man who could not be obedient, and stay awake to pray with Jesus in the Garden (Matthew 26:40-41), had assumed the responsibility of protecting Him - although Jesus had not authorised it. Previously, when people had tried to kill Him, He simply melted into the crowds and disappeared (John 8:59; John 10:31). He did not need Peter's protection, just his obedience. Like Judas, Peter did not really know Jesus. He should have watched and prayed instead of exposing himself to overwhelming temptation.
 
Peter's greatest protection, and ours, would result from Christ's arrest, trial and crucifixion: the protection against God's wrath and judgement and hell. But Peter wanted to stop it all. Of course he did not understand, but how often do we try to stop things that God is doing because we think we know better, at the same time as we fail to do what He has asked of us? Replacement obedience is wicked: King Saul was guilty of that (1 Samuel 15:17-26). Obedience must come first otherwise we will invent acts of 'obedience' which are really disobedience because God has never asked us to do them. Don't try to protect Jesus or the gospel, just advertise Him and speak the truth … and let Him do the rest.