The Spirit Realm existed before the Physical Realm.
The Spirit Realm is Eternal and has always existed. The Physical Realm was Created - .
God is a Spirit - . He has always existed. Where He exists is the Spirit Realm.
The Physical Realm is contained within the Spirit Realm.
God is omnipresent - . Though He is Spirit of the Spirit Realm He is in every place in the Physical Realm.
The New Birth makes us Spirit beings whose existence is in the Spirit Realm - .
Faith is the vehicle by which that which exists in the Spirit Realm Manifests in the Physical Realm - .
We are instructed to walk by Faith and not by sight - .
We are instructed to have our Minds transformed - . Carnal Minds produce Death. Spiritual Minds produce Life - .
We are instructed to walk in the Spirit - . This means we are to Live connected to the Spirit Realm.
Thw Word of God produces Faith - . It reveals the Truth about who we are. It connects us to God. It enables us to see things in the Spirit Realm. It enables us to Receive those Spirit Realm Blessings - .
20201009 Update
If you can imagine a large sphere inside of which is an infinitessimally smaller bubble you can better understand the relationship between the Spirit realm and the Physical realm.
The Spirit realm is filled by God who is Spirit. The Physical realm is inside the Spirit realm. It is temporal while the Spirit realm is eternal.
The Physical real was created to serve God's purpose. When His purpose is fullfilled there will be a new Heaven and new Earth. I suspect they will be Spiritual rather than Physical as they will be eternal with none of the diminishing characteristics of the Physical.
In essence, I believe the solely Physical realm will cease to exist and that which God called Good will be in the new Heaven and Earth as Perfect.
As new creatures (spirit) we live in the Spirit realm. Our bodies become merely the vehicle which our spirit uses to interact in the Physical realm.
To the extent our Minds and Emotions are transformed (renewed) is the extent to which the kingdom manifests in us and through us.
When Christ Returns our Body will be translated from corruptible Physical to incorruptible Spiritual.
Since our brain is corruptible Physical and contains all the information about the Physical Realm from our life experience, when it is translated into incorruptible Spiritual it will be cleansed of all those memories that would cause sadness and become Perfect.