Buy a sword but turn the other cheek

Jesus gave two commands that on the surface seem to contradict each other.

Do not resist the one who is evil. But if anyone slaps you on the right cheek, turn to him the other also.
Matthew 5:39

But now let the one who has a moneybag take it, and likewise a knapsack. And let the one who has no sword sell his cloak and buy one.
Luke 22:36

What is the point of owning a sword if you are forbidden to defend yourself against an attacker?

The main reason this seems contradictory is that many people misunderstand what Jesus meant when he said we are to turn the other cheek.

Jesus said that if someone slaps us on the right cheek we are to turn the other cheek.  It is an unfortunate fact that most people are right handed.  (I consider it unfortunate because I’m left handed and living in a world where everything is designed for right handed people can be inconvenient.)  If you are facing someone and hit him on the right cheek with your right hand you will hit him with the back of your hand.  You might cause some pain but you can’t do any real physical harm.

The purpose in striking someone this way is to insult him and express contempt for him.  There have been cultures in which this act would be considered a challenge to a duel.  Today it is possible that the person being slapped will try to kill the other without bothering with the formalities of a duel.  Jesus has forbidden us to respond in this way.

The command to buy a sword is easy to understand if you consider the context in which it was made.

And he said to them, “When I sent you out with no moneybag or knapsack or sandals, did you lack anything?”

They said, “Nothing.”

He said to them, “But now let the one who has a moneybag take it, and likewise a knapsack. And let the one who has no sword sell his cloak and buy one.”
Luke 22:35-36

Earlier Jesus had sent the disciples out to preach and heal.

And he called the twelve together and gave them power and authority over all demons and to cure diseases, and he sent them out to proclaim the kingdom of God and to heal. And he said to them, “Take nothing for your journey, no staff, nor bag, nor bread, nor money; and do not have two tunics. And whatever house you enter, stay there, and from there depart. And wherever they do not receive you, when you leave that town shake off the dust from your feet as a testimony against them.”
Luke 9:1-5

Because they were preaching to Jews they could rely on the Jewish custom of showing hospitality to meet their needs.  The territory they preached in was safe enough so that they didn’t need swords.  But after the resurrection Jesus was going to send them out into all the earth.  They could not be certain of finding people willing to offer them hospitality and they would sometimes need to defend themselves.

Today people use guns instead of swords.  A Christian has the right to buy a gun provided he does so legally but we must be careful to use our guns only for defense and not for retaliation.