Natural World
Earth
Air
Water
People
Animals
Plants
Built things
Stars
Planets
Spiritual World
God
Angels
Heaven
Hell
Demons
Satan
The Holy Spirit
Jesus
God
Note that these two worlds co-exist in the same place, and at the same time. A "veil" blocks our ability to see into the other world, but the spiritual world sees both!
We can sometimes "see" into the spiritual world when God lifts the "veil" from our eyes. Three examples:
Eden (Gen. 3:23-24)
Jacob (Gen. 28:10-17)
Jesus ( John 1:51, Matt.17:1-3 )
The spiritual world is just as real as the physical one.
In the natural world there is:
Birth
Death
Time
Seasons
Ages
In the spiritual world there is:
Eternity
Timelessness
Immortality
Two types of worship (Ephesians 2:11-22) ( John 4:21-24)
Serving God under the O.T. was using rituals and objects of physical nature (sanctuaries, alters, symbolic sacraments, et) to attempt to approach God as a unworthy alien seeking favor.
Serving God under the N.T. is using spiritual objects (prayer, praise, worship) in spirit and truth ( having the Holy Spirit within, and a sonship relationship with God) to commune with God as a spiritual being.