RIP is a common condolence uttered when someone has died. Nevertheless, I, though unwillingly, advised a mischievous kid who was trying to get into the room where a tired elderly man was in (resting peacefully?). I said:
Hey, don't make noise and go in that room. Let him rest peacefully!
Note: I was not pretty sure whether the man was sleeping but it was confirmed that he went in that room to take rest. That's why I didn't use let him sleep peacefully.
After uttering that sentence, I was shocked for a while. And there comes the question -
May we use 'rest peacefully' if want to mean 'let someone alive rest in ataraxis!'? What's the outcome of Rest peacefully Vs. Rest in peace?
Searching dictionaries or the internet for "rest in peace" gives results of condolence and nothing else.