Some religious/spiritual systems impose ethics on you as a set of rules or present a moral philosophy that you are supposed to adhere to. Other systems don't have a premade set of ethics, but aspects of working within the system may help you become aware of your own personal ethics. (Maybe this could be called "leaving more of the process of deriving an ethical system up to you.")
(Many religions include both streams.)
I've always approached religion/spirituality as a way of helping me figure out my own personal ethics, and have avoided following religions that try to impose ethics (although I've mined their sources for ethical ideas that might work for me). But I never quite put into words that I was doing that.