It is a short jump from accepting full participation of a Christian in a state/government function, specifically in bearing the short sword, or today, weaponry as in guns from Romans 13 (which does not ascribe that function to Christians, but in part, for Christians), to advocating protection with guns in both public and private places, such as at church, and at home. I can see that such logic is hardly a stretch at all.
The only problem is Romans 13 and its context (the end of Romans 12). And more than that, but better put, along with it, our Lord’s teaching and example carried to its climax in the gospel accounts at the cross, by his death on the cross. Particularly Matthew 5 puts in question, and at last gives the lie, I think, to the supposed right, or option for a Christian to bear arms for self-defense at all, a truly radical position, but one that is in step with our Lord.
And so there are churches which are training people for security,some with weapons in hand, ready to stop any would be assailant. And there are Christians who have a gun loaded and ready to retrieve and possibly fire at any unwelcomed intruder.
There is no question that the state is in place according to Romans 13 in significant part to protect its citizenry, and specifically in the passage, for the good of God’s people. But in the way of Jesus there is no place for guns and their use against other humans. If a Christian can serve in the role of the state, then in that sphere there surely is a time and place to use weaponry as a last resort. I don’t see scripture opening up that door, but if it does, it would be relegated to that. For us in Jesus, there is only one way, the way of the cross, the way of death and resurrection, which alone is a witness to Jesus and the gospel. Taking up guns for the possibility of self-defense and even protection of others in a worst case scenario, even if never used at all is a compromise, and a tacit denial of the gospel.
We are not only to proclaim the gospel as the church, but to live it out as witnesses, through and through. By what we do and refuse to do, we either witness to it, or we don’t, in fact, we may very well be denying it. If you question this, begin to read through the gospel accounts: Matthew, Mark, Luke and John. Read beyond that, the rest of the New/Final Testament, and see whether or not this is true. A straightforward reading of it, I think will at least put into question our dependence on guns.