Ephesians 6:10-17 (KJV) Finally, my brethren, be strong in the Lord, and in the power of his might. Put on the whole armour of God, that ye may be able to stand against the wiles of the devil. For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high [places]. Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand. Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness; And your feet shod with the preparation of the gospel of peace; Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. And take the helmet of salvation, and the sword of the Spirit, which is the word of God:
This passage deals with standing against the wiles of the devil. It does not deal with self-defense in the physical realm.
We are encircled by enemies and we have the right of self-defense. Russia is on the march with new technologies in atomic weapons and rockets that the USA does not have. Our weapons are half a century old. China also is on the march and we see what they have done to Tibet and others and what they are trying to do to Hong Kong. The word of the Chinese is worthless. They are bent on world domination just as are the 22 Arab nations and other Islamic states who are commanded to execute all non-Muslims in the Quran.
Jesus said to sell your cloak and buy a sword, meaning a dagger, not a Bible.
Here is a case from Florida where a man in self-defense saved the lives of himself, his wife, and his 11 year old son when a man attacked him with an AK-47 in the middle of the night in Miami while they were asleep in their van. He emptied a Glock in the criminal's chest in self-defense. If the heathen know what Jesus asks, why can't the Christian understand?