I'm not sure what the meaning of "I believe god exists and he has a plan" is, if the plan is beyond our understanding. What do people actually believe? Sure, the words will be "I believe in god", but what are the consequences of this belief?

If anything can happen inside this incomprehensible plan, what is different from there being no plan? If you don't believe anything concrete about the plan, if there is nothing that is impossible because it would be against the plan, then isn't everything just as it would be if there was no plan and no god?