Origins of Sin/Satan and Angels

Trying to fit together these pieces of the jigsaw. Would be glad for all to throw in some thoughts , scriptures regarding this.

We know about Adam and Eve and how they sinned, but what about before them? Here are some questions to stimulate thought.

1. Who was Satan?
2. How did he fall?
3. When did he fall?
4. What about the Angels?
5. When and how did they fall?
6. How many fell?

Here's a link to a book called 'know your enemy' by Zac Poonen -it's free, it should answer all of your questions and give you encouragement in facing the powers of this world and Satan!

http://www.cfcindia.net/web/mainpages/book_window.php?book=know_your_enemy