The King James Version is definitely not the best Bible translation, but it has one thing no modern version has …
… plural and singular yous.
Most languages have a word for you in the singular and a word for you in the plural. English no longer has one, so various sections of the country have found various ways of making up for this.
In the south, people say y'all. Of course, that's become so common that sometimes it's used in the singular as well as in the plural. So sometimes, a southerner will use "all y'all" to refer to a plural you.
In New Jersey, they say "yous guys" or just "yous." In the west, "you guys" is most common, and it's sometimes even used when talking to a group of girls!
In 1611, when the King James Version was translated, English still had a singular and plural you. If you were talking to just one person, you said "thou," and if you were talking to two or more, you said "ye." The accusative version of those words were "thee" and "you" (like "me" is the accusative version of "I.").
Thus, in the KJV, you can instantly tell whether the Scriptures are speaking in the plural or singular by whether thou, thee, and thy are being used (singular) or ye, you, and your (plural).
Matthew 5:16 stands out to me. There we are told, in the KJV, "Let your light so shine before men, that they may see your good works, and glorify your Father in heaven." Because of that verse, we sing, "This little light of mine, I'm going to let it shine."
We should be singing, "This great light of ours, we're going to let it shine."
The "your" in Matthew 5:16 is plural. It is not singular. The context is a city set on a hill that cannot be hidden, not an individual with a candle in the midst of the world.
Isaiah 60:1-5 describes the incredible power that comes when God's people obey Matthew 5:16. It really works! When the light is corporate, it is like a city set on a hill; it can't be hidden. People notice!
1 John 2:27 is another example. I don't need anyone to teach me? The Holy Spirit will guide me into "all things," and these "all things" I'm guided into will all be "true and not a lie"?
Once again, all the yous in that verse are plural. God is promising the local church that if they will trust in him, he will guide them into all things, and everything he guides them into will be true and not a lie.