Punctuation in your King James Bible remains a mystery to most. For one thing, in the earlier posts on orthography it was explained that the rules of punctuation changed in the early 1700s, and that the work of Parris in 1762, and of Blayney in 1769 brought the punctuation of the King James Bible up to date with modern punctuation without changing any words or translations.
The rule for parentheses does not appear to have changed from 1611 until now. A set of parentheses is used whenever the translators identified a thought within a thought. Wherever parentheses are employed in your bible, it is possible to read the surrounding verse or verses without the words in parentheses and have it still make sense. Take a look at Romans 1:13.
Now I would not have you ignorant, brethren, that oftentimes I purposed to come unto you, (but was let hitherto,) that I might have some fruit among you also, even as among other Gentiles. Now read that same verse without the words in parentheses. Now I would not have you ignorant, brethren, that oftentimes I purposed to come unto you, that I might have some fruit among you also, even as among other Gentiles. It still makes perfect sense.
Sometimes whole verses are put in parentheses. II Corinthians 6:2 is such a verse. Why was in put in parentheses? Read II Corinthians 6:1 and II Corinthians 6:3 without the middle verse. It reads perfectly without a hitch: We then, as workers together with him, beseech you also that ye receive not the grace of God in vain. Giving no offence in any thing, that the ministry be not blamed, II Corinthians 6:1+3. The translators recognized II Corinthians 6:2 as being a thought within a thought: (For he saith, I have heard thee in a time accepted, and in the day of salvation have I succoured thee: behold, now is the accepted time; behold, now is the day of salvation.)
In later posts we will explore the punctuation further. For now, I hope my readers find this both interesting and helpful.