Regarding a previous comment, the people, like general Ackbar saying “May the force be with you” are not saying it as a general “God bless you” type of thing, they’re saying it because they believe it, mean it, and hope for it.
Han says it to Luke before the Battle of Yavin. He doesn’t believe it.
It’s the Rebel “good luck” saying. Up until Luke becomes a Jedi, no one has seen the Force in action and there’s no reason they’d believe in it.