Peter here acted on his emotions, he loved the Lord and wanted to deffend him, and not let the high priest's servants take him away. He forgot the message the Lord had given them that same day, how that he had to go away so that God would be glorified. Glorified through the death of our Lord Jesus Christ. He simply forgot what the Lord Jesus had told him and acted on emotions and his feelings.

Is this not like us? how often do we come across circumstances in life and we just act on our emotions. We don't think or consider what God would have us to do, but just act on our feelings and emotions. This is not how God wants us to act in our life down here. He wants us to bring glory to God in our life, and how can we possibly bring God glory by acting on our emotions and feelings. We CAN'T. We have to sumbit yourselves to our God in these circumstances, and just stop and think about, what it is that God would have us do. Some times God may have already shown you this answer, and prepared you for this circumstance, and other times we have to knell down before God and ask him to show us and guide us through his precious gift of the Holy Spirit, into the way in which he would have us handle this situation.