No matter how much effort you put in, throwing a pebble into a lake will create waves.
With the mind, all you can hope to achieve with clear knowledge, is that those waves are not imagined into a tsunami.
Mind having imagined tsunamis in the past will again try to do that. Reason, another part of the mind comes to the rescue.
When all these forces work together, peace results. Some call it unification of minds. But in my opinion its just nicorette subbing for cigarettes, far less toxic.
You have it, you lose it, you have it again, and so goes the waves in the real stillness which never really changes.
Another perspective; what is calm waters for a super oil tanker feels like a storm to the little sailboat caught in a the middle of the ocean.