Obi-Wan Kenobi: Well, the Force is what gives a Jedi his power. It is an energy field created by all living things. It surrounds us and penetrates us; it binds the galaxy together.

Anakin Skywalker: Master, sir, I heard Yoda talking about midi-chlorians. I’ve been wondering…what are midi-chlorians?
Qui-Gon Jinn: Midi-chlorians are a microcopic lifeform that reside within all living cells and communicates with the Force.
Anakin Skywalker: They live inside of me?
Qui-Gon Jinn: In your cells, yes. We are symbionts with them-
Anakin Skywalker: Symbionts?
Qui-Gon Jinn: Life forms living together for mutual advantage. Without the midi-chlorians, life could not exist, and we would have no knowledge of the Force. They continually speak to you, telling you the will of the Force. When you learn to quiet your mind, you will hear them speaking to you.
Anakin Skywalker: I don’t understand.
Qui-Gon Jinn: With time and training, Annie, you will. You will.