Now let’s look at some basic rules regarding commas:
Always place a comma before a conjunction introducing an independent clause. In other words, place a comma between two independent clauses separated by a conjunction. Independent clauses have a subject and a verb, and they can stand alone. (The situation looked hopeless, but there was one remaining chance for success.) or (The situation looked hopeless, but I didn’t believe it.)
However, do not join independent clauses with a comma if they are lacking a conjunction. They need to be joined with a semi-colon, or they can be cut into two separate sentences. (The situation looked hopeless; there was one remaining chance for success.) or (The situation looked hopeless. There was one remaining chance for success.)
A common mistake made with the comma is to separate a dependent clause from an independent clause when they are joined with a conjunction. (I was told the situation looked hopeless but didn’t believe it.) Each clause must have a subject in order to need a comma before the conjunction.
“The comma, which seems to cup the sense of the preceding phrase and hold it out to us, timidly and respectfully, is one of our greatest breakthroughs. The civilizing influence of this punctuation aid derives partly from its odd shape, the shape of mosquito larvae and sea horses: close inspection reveals the implied high culture of its asymmetrical tapering swerve, so distinctly an advantage over the more rustic period.” –Nicholson Baker
The punctuation error that seems to occur most often in the hundreds of manuscripts crossing my desk each year is misuse of the comma. It is important to learn when to use and when not to use commas. To make matters worse, The Chicago Manual of Style, The Associated Press Handbook, and most grammar books list different rules. Most Christian publishers have their own style sheets, but they basically follow The Chicago Manual of Style, which is the standard in the book publishing industry. Since it is costly, I suggest you buy Strunk and White’s The Elements of Style to help you with grammar, punctuation, and word usage. First copyrighted in 1935, this little 92-page book is packed with all the basics. It can be purchased inexpensively at any secular or on-line bookstore.