Josh Gibbs writes:

“While it might be anachronistic to read it this way (modern Christianity has likely blown the idea of the ‘sword of the Spirit’ way out of proportion), it seems best to me that we understand two entirely different, separate swords in Christ’s statement, ‘He who lives by the sword will die by the sword.’

“Christ’s ministry has established a dichotomy between the violence of man and the violence of God, the power of man and the power of God. Further, Christ has made myriad claims about choosing to live well in this life or in the next life (parable of Lazarus, ‘you have your reward’ statements, etc). Further still, Christ has warned his apostles many times about the suffering and persecution they will have to endure for following him, but about the great rewards they will receive in glory for doing so.

“Christ’s statement about living and dying by swords  is then a wildly clever ‘You must choose . . . ’ manner of claim: ‘He who lives by the sword (of the Spirit) will die by the sword (of thugs/the State),” or conversely, “He who lives by the sword (of thugs/the State) will die by the sword (of the Spirit).’

“This reading might answer rather obvious doubts we have about Jesus’ statement were we to take the two mentions of ‘sword’ to be the same sword: when Jesus claims, ‘He who lives by the sword will die by the sword,’ He is being led away to die by the sword of the State. Has He lived by the sword? Indeed, but the sword of the Spirit.”

In support of this, especially the last, we can observe that the only use of “sword” in Matthew outside the context of the arrest is in chapter 10, where Jesus says that He is wielding a sword.  He comes to divide families and neighbors from one another, a fact evident in the scene in the garden, where Jews with sword come to arrest a Jewish teacher, where a disciple with a sword attacks a group led by another disciple.