Did Jesus teach pacifism?
My understanding of Jesus' teaching is this: Jesus advocated love and patience as opposed to hatred and revenge, but not a total pacifism that forbids even self-defense. In Luke 22:36, Jesus seemed to be advising the disciples to use self-defense when necessary, but nothing more. He didn't advocate violence as a way of doing things, for he said that two swords are enough for the eleven disciples1 and in Matthew 26:52 rebuked Peter for attempting to start a violent revolt. Self-defense isn't contradictory to Matthew 5:39, for that passage refers to a slap or insult, not a hard punch that would constitute an attack. Since most people are right-handed, striking someone on their right cheek would typically be done by slapping them with the back of one's hand. Seen in the context of Matthew 5:38-42, Jesus' point is that we shouldn't take revenge, not that we cannot defend ourselves.
In Matthew 10:34, Jesus was referring to the fact that his coming forces people to choose sides: either they will choose to do what's right and follow Christ, or they will choose to avoid persecution and reject him. The result is that even families will be divided, as those who reject Christ turn on those who accept him.2 Since Jesus would rather have everyone repent and turn to him,3 he was not advocating this conflict, nor was he happy about it; rather it came about as a result of people choosing to reject him.
Did Jesus practice what he taught?
Did Jesus violate his own teaching by talking back after he was struck instead of literally offering his other cheek? Again, Jesus' original teaching in Matthew 5 was against revenge, and he was not trying to get back at those who had arrested him in any way. He was not even insulting those who had arrested him. All he did was raise a valid question: why had he been struck, if he were telling the truth? There is a difference between submission and prostration. While Jesus submitted himself to the authorities and did not fight his arrest and crucifixion, he was not obliged to not challenge the authorities when they did something wrong, such as striking him for no good reason.
http://www.rationalchristianity.net/jesus_pacifist.html