May the Force be with you is the catch phrase of Star-Wars, but does it make any sense?
Obi-Wan himself explains the force like this:
LUKE: The Force?
BEN: Well, the Force is what gives a Jedi his power. It's an energy field created by all living things. It surrounds us and penetrates us. It binds the galaxy together.
If "it surrounds us and penetrates us", how could it not be with you?