When we think of shadows, we think of some object that blocks the light and thus produces a dark area or image, which we can see.
Shadows are also associated with something ominous, oppressive, sadness or gloom, as in a shadow has been cast over the country or over my life, etc.
But in the Bible, or the Spiritual realm, there are two environments.
The first is reality, and the second is the shadow.
Reality exists only in Heaven and as stated in John 1:1-5:
1 In the beginning was the Word, and the Word was with God, and the Word was God. 2 He was with God in the beginning. 3 Through him all things were made; without him nothing was made that has been made. 4 In him was life, and that life was the light of all mankind. 5 The light shines in the darkness, and the darkness has not overcome it.
The darkness is all of creation. We are the darkness, or the shadow.
The light originates in Heaven and the light passes through Christ, which casts a shadow into creation.
We are the shadow.
If we look back toward the light, we must see Christ, who is our path to the light.
Light is truth and life and so forth.
In the shadow, there is no life, no existence. A shadow has no substance, no texture, no color, no smell, nothing. It is merely an image produced when light is interrupted and thus the light, which is God and truth, etc., then the shadow indicates the lack or that light, truth, etc.
So, creation, you and me, etc. are only shadows or nothing, unless and until we can get past the object that interrupts the light and get back into the light. That object is Jesus Christ and to get on the other side of the barrier and out of the shadow and into something that makes us real, we have to believe in Christ.
In the shadow, you are unsaved, lost, nothing. In the light you are saved, found, something.