The Force Awakens! There has been an Awakening! Excitement right there, all I needed. But the question remains, why was the Force asleep? If we recall from the PT, there are numerous quotes from Mace and Yoda speaking of the fact that their ability to use the Force had diminished, essentially due to the Sith bringing the Force out of balance.
At the end of RotJ, with the Emperor and Vader dead, we would expect the Force to go back into balance. What event or circumstance made the Force not expand and pervade throughout the galaxy after the death of the Emperor and Vader? We don’t know much about the time between RotJ and TFA except there is a First Order, Knights of Ren, at least two bad Force-users Kylo and Snoke. Why hasn’t Luke passed on what he learned and where is he?
I think most of this can be explained by one hypothesis. The First Order has a way to track down those that use the Force. Not a person that does it but a Force detection device that I believe is located at the Starkiller base. The real reason Kylo is looking for the lightsaber is to track down Luke, who is no longer using the force, and use the Starkiller weapon against him. Snoke believes Luke to be the only threat to his eventual galactic rule and Kylo wants to avenge Vader, whom he worships. Under this hypothesis, the Force Awakens whenever someone uses the Force. It was asleep because Force users have had to withhold these powers to avoid detection.
What evidence do I have for a force detection device? The rumors give us three pieces of information that back up the idea. Firstly the First Order shows up to Maz’s Castle after Maz uses the force to show Han, Chewie, Finn, BB-8 and Rey a flash-back vision. Yes, we know that the First Order is tracking them but the Falcon has always been able to avoid tracking after jumping to hyperspace (except when a tracking beacon is placed on it). According to the rumors the First Order is not on their tail when the head to see Maz. Maz has a vision, First Order shows up on their doorstep after firing their Starkiller weapon to destroy the castle before landing. Although it is certainly possible that a Force-sensitive such as Snoke could detect them with Force abilities, a machine like a computer might be needed to pinpoint the exact galactic coordinate and send this information to the Starkiller weapon base in order to blow up the castle and allow Kylo to land directly at the site. Second, the flashback vision shows us the destruction of Luke’s Jedi academy. Its location was no doubt a secret fiercely guarded by Luke to prevent any attacks on the future of the Jedi. He will have learned the lesson of hiding the academy from Yoda and Ben by their actions after the birth of the Empire. How would the Knights of Ren or the First Order have found them to destroy it without a device to track the use of the Force? Third there are no Jedi running around using the Force, as far as any rumors we have heard there are only 3-5 potential light side force users around: Certain: Luke, Maz, and Leia. The potentials are Rey (Most likely aware or trained) and Finn (not trained or aware). Luke learned that the First Order can track the use of the Force and sent word to Leia , Maz and any other living Jedi that they were in danger and to not use the force until he returned. Luke being the most powerful Force user alive had to hide like Yoda, likely heading to Vader’s castle to hide himself further and learn if he could hide his use of the force.
The line from the teaser would most likely then be from one of two times the light uses the Force in the films. Maz begins to use the force to show the vision. Or at the end when Rey shows up to where Luke is hiding. I tend to believe it is from right before the attack on Maz’s castle rather than the end of the film as Maz leading the vision would be the first use of the Force. The only other place I can see it is at the VERY beginning of the movie with Snoke giving Kylo his marching orders.