What is a parenthesis in a sentence?
A parenthesis is an inserted word, phrase, or clause placed in the middle of a sentence that already makes sense, to enlighten or describe it further. It is set off by little curves, or parentheses, showing that the added material is parenthetical and not essential to the main sentence.
Les explains that in ordinary English usage, you can have a sentence that makes sense on its own, and then you think of something you can stick in the middle of that sentence to enlighten it and describe it a little bit. You open your sentence up and put a parenthesis in the middle, with little curves around it. He illustrates this with Romans: after chapter 8’s assurance that Christ died for us, God is for us, no one can be against us, and neither principalities nor powers can separate us from the love of God, the next section seems to have no real connection. Then chapter 12 verse 1 is the other side of the parenthesis, and its “therefore” reaches back to what he just finished in chapter 8.