"Just as he was speaking, Judas, one of the Twelve, appeared. With him was a crowd armed with swords and clubs, sent from the chief priests, the teachers of the law, and the elders." NIV translation
A mob was sent by the Sanhedrin (religious establishment) and was led to Jesus by Judas. We say mob because, as we see here, some of them only had clubs as if they were not normal guards. They were joined by some Roman soldiers as well as regular temple guards. This is a reminder to us that Jesus was not a part of some religious establishment.
"Now the betrayer had arranged a signal with them: 'The one I kiss is the man; arrest him and lead him away under guard.' Going at once to Jesus, Judas said, 'Rabbi' and kissed him." NIV translation
It is sad to think that the devil used an act of affection to betray Jesus. Even the term rabbi which was a sign of respect was twisted to show contempt. We are reminded by this that the devil is a liar and that he tries to make sin palatable through flattery.
"The men seized Jesus and arrested him. Then one of those standing near drew his sword and struck the servant of the high priest, cutting off his ear." NIV translation
Peter drew his sword and cut off the ear of Malchus. We are reminded that, on the way to the garden, Jesus had told of the fact that Peter would deny him. This was probably an attempt on his part to show that he would not betray Jesus like the others.
"'Am I leading a rebellion,' said Jesus, 'that you have come out with swords and clubs to capture me? Every day I was with you, teaching in the temple courts, and you did not arrest me. But the Scriptures must be fulfilled.'" NIV translation
Jesus answered their violence with the fact that He had walked among them in peace. They could have easily arrested Him at any time as He was in the temple courts every day. He also reminds them that this is all a part of God's plan as He says the Scriptures had to be fulfilled.