Good answer to the question. Meanwhile, the example brings up the issue of religious speech.

How does religion have anything to do with this?

“Love thy neighbor” is not formal speech. It’s religious speech. “Thou shalt not kill” is not formal speech. It is religious speech.

It's the style specifically of the King James Bible. If you read a different translation of the bible, you get different styles.

It may have been formal speech when translated into the language of the first generally distributed translation of the Bible, but now, it is spoken only in religious context.

It was stylized when it was translated. According to Wikipedia, because the English language was undergoing great change at the time it was translated, the panel of translators deliberately "avoided contemporary idioms, tending instead toward forms that were already slightly archaic." It uses thou/thee and ye/you as singular and plural pronouns, but by this time you was usually the singular used. The King James Bible wasn't formal when it was published, it was stilted.

If you have a religion and you don't happen to refer to the KJB, you probably don't speak like this in a religious context.

I don't think the King James Bible was the first generally distributed translation of the bible. I might guess that the Gutenberg bible was, which was a Latin Vulgate edition, not English. I doubt the KJB was even the first widely distributed English translation.

Legal context is formal, but it wouldn’t use those words. Academics use formal speech, though some of that is jargon, as is some legal speech, etc. Newscasters use formal speech. Journalists use formal speech. Teachers use and teach formal speech.

There are levels of formality. An academic paper is typically more formal than a newscast, which is typically more formal than the average high school English class.

Meanwhile, informal speech similarly has many dialects, and slang is a form of jargon, though perhaps it is understood by a larger group of people.

You'll need to first establish that the prefix trick is specific to some level of formality or informality before you start trying to identify which it belongs to.

-- 
SuStel
http://trimboli.name