Every church that I've been in has not advocated that Christians should not have arms.
However, when attempting to show why Christians should be armed, some may have used the wrong scriptures to make their case.
They would use:
 
Luke 22:36 Then said he unto them, But now, he that hath a purse, let him take it, and likewise his scrip: and he that hath no sword, let him sell his garment, and buy one.
37 For I say unto you, that this that is written must yet be accomplished in me, And he was reckoned among the transgressors: for the things concerning me have an end.
38 And they said, Lord, behold, here are two swords. And he said unto them, It is enough.
 
To try and say that Christians should be armed. However, when those three lines are taken with:
 
Matthew 26:50 And Jesus said unto him, Friend, wherefore art thou come? Then came they, and laid hands on Jesus, and took him.
51 And, behold, one of them which were with Jesus stretched out his hand, and drew his sword, and struck a servant of the high priest’s, and smote off his ear.
52 Then said Jesus unto him, Put up again thy sword into his place: for all they that take the sword shall perish with the sword.
 
Then it is not as clear cut.
Jesus never said to "use" the weapon
This case was where armed men were coming against them. Yet, Jesus told Peter to put up his sword.
Then he warns against taking up weapons. It's not a contradiction.
Luke 22:36-38 appears to be for the fulfillment of scripture, maybe even:
 
Isaiah 53:12d  and he was numbered with the transgressors;