A tired day would normally lead to an undisturbed sleep.
Alas! Nights are all but undisturbed; for the mind plays upon the day gone by and upon what lies ahead.
Wonder, if the long sleep that the body goes into, on the soul passing away, would ever be a phase of “rest in peace”?
As is believed, in death accountability cannot be evaded, and this is probably why “rest in peace” remains an expression for those whom you know and who have nothing else to offer when you die.