This question delves into a very crucial understanding of what constitutes a “human”. 
Notice, Gen. 2:7, “Then the LORD God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being.”
From the narrative in Genesis, man is composed of:

1. Matter: our physical body comes from the “dust of the ground” that has no life. 

2. Breath of life: this physical body became a”living soul/body/being” only after this component was given by God. This did not come from “earth and not earthy” nor “made by hands”.. It came from God, therefore, heavenly and spiritual. This “breath of life” is the energizing power that brought life to the material body. This is not “oxygen” that we breath since oxygen is “matter” not “spiritual”. This is what we now call the “spirit of man”.
Truly, the “flesh is weak” and is temporary as the “temple” is temporary. As we are the “temples of God”, He intimated their temporal nature in the Old Testament times by dwelling from tabernacle which was pitched from place to place, to 1st temple to 2nd temple which was destroyed in 70 AD. The Spirit of God then dwells fully in man-Jesus(anthropos) at river Jordan after coming out of water baptism (Mk. 1:10), and dwelled among the apostles in Pentecost (Acts 2:1-13) and others, since then. This is the “spirit power of God” that seals us to the body of Christ, teaches us the “mind of Christ” to be like him.
The physical body will die and at death, the body goes to “hades”(hell/burial place” and deteriorate, while the “spirit of man” goes back to its Creator. As Jesus is the Creator Elohim in Genesis 1, YHVH Elohim in Genesis 2 and the Logos in John 1, no wonder Jesus said to the thief in Golgotha, “today, (at death) you shall be with me in paradise”. 
Without a body, this “spirit of man” can not express any “action or activity” much like our “mind” can not do anything without a body. Hence, this “spirit of man” has to be placed in another body, this time an “immortal body” for the “firstfruits” at Christ’s return, then the “latter-fruits” for action to be expressed.