The human nature or man is tripartite in the sense that he is three-way or three-parts. These parts are the human spirit, the human soul and the human body. This view is also held by a lot of theologians. But many of them do not hold a univocal arguments in justifying this claim.
I believe this theory of human nature answers most of your questions about the human nature. This theory clears and also avoids certain confusion and contradictions in some other theories of human nature. This inquiry will help you understand the origin, nature, purpose and function of the human spirit, body and soul.
Man is first and foremost a spirit being though he is also made up of body and soul. Man is a spirit that has been given a soul to live in a body. Again, Man is a spirit that has been given a soul and a body to function on earth. Among these beings: body, soul and spirit, the spirit was the first to exist.
For he chose us in him before the creation of the world to be holy and blameless in his sight. Ephesians 1:4
Before I formed you in the womb I knew you, before you were born I set you apart; I appointed you as a prophet to the nations. Jeremiah 1:5
The second being to come to existence is the body. And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul – Genesis 2:7. So the human body was the second to come into being.
Then finally, the soul. And the LORD God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul – Genesis 2:7.
It was the soul that made man a living soul, being, creature or person. So we are living creatures because we have a soul. The soul is what makes man the living being that he is on earth. The soul defines his existence or who or what he is on earth. This means that the moment the soul leaves the body, man dies or the moment the body dies the soul leaves the body.
See detail account on the human body.