"Spirit" is not an experience "we have".
I find that hard to grasp.
Rightfully so. It is ungraspable.
But how can we understand it and reach the peace you talk about?
We can’t understand it. We can only understand experience. The source of experience is non-understandable, although it is ever present. But that is only half of the pointer. Some people may well “get it” by hearing only that half. Lucky ones, those are.
For the rest of us mortals there is the other half: we cannot understand Truth but we can understand what is false. Look at the false, recognize it as false and it dissolves naturally and effortlessly and Truth “becomes known”.
When we are children we believe in Santa Claus. One day we figure out it really does not exist except in our imagination so its falseness dissolves forever. It is impossible to re-instate Santa Claus. And you live free from that falsehood, and its harmless implications, although it can be really disappointing for some children.
So, the pointer is given: look into your experience and find "I". Where is it? Focus on the inquiry. Look carefully.
If you look from the correct angle you will see that “I” is exactly like Santa Claus: an image or concept, but associated with a body and a personality in this case. This is not an analogy. The process of seeing the false as false is exactly the same.
The problem is that we have accumulated an enormous network of beliefs and justifications about who or what we are since childhood and even in spiritual teachings, such as those who teach us that “we are” a soul in evolution. So we have developed a serious emotional stake in this “I”. That poses a considerable obstacle to the realization of Spirit. The implications of this falsehood are far from harmless, like Santa Claus’ was.
So, the work is to study the mind, stop justifying our petty negative emotions, because they function like glue for the psyche, stop repeating wrong beliefs, and then, piece by piece recognize that all those thoughts and emotions and sensations do not equate with “I” in any way at all. If we keep at it and keep discarding the false what is left is the non-understandable Spirit which is devoid of qualities and thus the personality and body relax and live in peace.