In discussions/debates with religionists I like to point out to them that "my God says so" is not an argument, and an argument plus "my God says so" is not a better argument.
That is in addition to the veracity of their claim that they can accurately discern and convey the will of their respective gods.
It is worth remembering for instance, that the bible was used to both defend and condemn slavery.
It's useful to remind ourselves that at least when it comes to Christianity, this is the view of a minority, at most a third. It is how authoritarian / fundamentalists types view things, but in my experience, is in practice not the view of the majority of liberal Christians. The most they've ever done in this regard to me is to draw a red line requiring belief in at least some form of the Christian god, even if basically non-interventionist. And most of them don't even do that.
But in fundamentalist circles, it's all about being RIGHT rather than being GOOD. And they are greatly threatened by others not subscribing to their RIGHT beliefs.
Or "my religion says I can't let you do that." That is BS. I don't think there is a concept of "sin" outside of religion, and then sin is what the priest doesn't like or wants to restrict. I could be here all night on this thread.
A religion may like to suggest best practice, but it has no right dictating to anyone how they should live their lives. Encouragement with unconditional love and empathy is what any true religion should be propagating, not giving power to a few of the 'chosen' to rule others in fear.