“LUKE SKYWALKER: What do you see?
REY: Light. Darkness. A balance.
LUKE: It’s so much bigger.”
As you may know, the balance of the Force is a concept introduced in the Prequel Trilogy and later developed in The Clone Wars. It was also referenced in The Force Awakens. According to George Lucas, Anakin Skywalker restored balance to the Force by destroying the Sith in Return of the Jedi.