In my country, whereas it has an eastern, religious type of the culture when someone wants to say that an event must happen 100% in order to achieve something or when someone wants to say that it is not "very" necessary to do something and generally when someone wants to emphasize that a specific belief is not very necessary, says:
It is not a divine message / voice for you to do that.
It is not a divine message / voice that it must happen. etc.
I am looking for an idiom, expression in AE for "divine message / voice" in the ways that I used in above self-made / translated sentences. I would be thankful if you could help me.