KJV:
For he is the minister of God to thee for good. But if thou do that which is evil, be afraid; for he beareth not the sword in vain: for he is the minister of God, a revenger to execute wrath upon him that doeth evil.
NASB:
for it is a minister of God to you for good. But if you do what is evil, be afraid; for it does not bear the sword for nothing; for it is a minister of God, an avenger who brings wrath on the one who practices evil.
KJV:
By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain.
NASB:
by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain.
KJV:
Have ye suffered so many things in vain? if it be yet in vain.
NASB:
Did you suffer so many things in vain-- if indeed it was in vain?
KJV:
I am afraid of you, lest I have bestowed upon you labour in vain.
NASB:
I fear for you, that perhaps I have labored over you in vain.
KJV:
Let no man beguile you of your reward in a voluntary humility and worshipping of angels, intruding into those things which he hath not seen, vainly puffed up by his fleshly mind,
NASB:
Let no one keep defrauding you of your prize by delighting in self-abasement and the worship of the angels, taking his stand on visions he has seen, inflated without cause by his fleshly mind,