Comma before because

I couldn't find quite what you are looking for, specific to 'because'. Here is a good basic introduction to COMMAS, and if you google the word, you'll find a lot of sites with more information and examples.

'Because' normally introduces a dependent clause, and dependent clauses are normally restrictive, hence taking no comma. When sentences and their clauses get too long, however, a comma may be necessary for clarity.

Hope this helps.

Yes, yes.  Of course we need to think about what we are saying and about what we might accidentally be saying in any given written passage.  And we must insure that unintended meanings are avoided.

On the other hand, we must assume at least a little intelligence and common sense in the reader.
No reasonable person would ever think Nixon was going to resign because someone's sister worked in the White House, for heaven's sake! 

(Nevertheless, I do agree that the comma helps in this case.)

CJ

Your comment "you often need to think about the contents of your statement" is VERY accurate, and your internet resource has given an excellent example of who people don't think about the contents. The resource has considered the wrong aspect of this sentence. It's these inappropriate examples that cause so much confusion when punctuating. The consideration here is the 'subject' of the sentence.

The reason a comma is not used before "because" is because the subject of this sentence is "I knew", not "President Nixon would resign that morning"

To explain ...

What this sentence is really saying is I knew that 'insert information' because my sister worked in the White House, and she called me with the news. You can clearly see in this case that you would not place a comma before "because." However, in both cases there should be a comma after house as she called me with the news is an independent clause.

The very use of "because" dictates that the following clause will be sub-ordinated in every case, and sub-ordinated clauses are not separated by commas.

I hope I have explained this well enough to clarify your confusion. In short, never use a comma before because*.

**Disclaimer* unless the writer is being 'creative' and knows the rules he/she is breaking

I'm sure your intended recipient is delighted to be assisted in such a charming and generous manner. To the point, one shouldn't 'always include commas and periods inside quotation marks'. That only applies to American English. British English, for one, places punctuation outside the quotation marks (single in the first instance and often called inverted commas or speech marks) unless the punctuation applies to the quoted material.