Peace does not save us, yet it is the portion of a saved soul.
Amen!
The problem the Calvinists have is on an individual basis being sure they are the elect.
There is always a possibility that they are not and they cannot really know this until the reach the end of their lives.
It is always possible that a sin could take them away from God and thus show that in fact, they were never truly 'elect' in the first place.