In a heavily symbolic section of scripture, we are told that Israel will produce the Messiah. The enemy will try to destroy the Messiah but will fail. God will then protect His people for the remainder of the Tribulation as we're reading about them now. The reason we come to these conclusions is a combination of three things. Reading the whole text, recognizing quotes from previous texts, and allowing what we do know to sort out what we don't.
1. If something hasn't been explained before in the Bible, it's about to be.
2. If you haven't read the first 65 books of the Bible, the 66th isn't going to make a lot of sense to you.
3. A sign is something that is meant to point you to something else.