Here is a great explanation and well put together understanding of this topic:
Premise
Traditionally most people believe that there is a ghost-like “spirit” inside of our bodies, and when we die, this spirit floats away somewhere, preferably heaven.
I will show that the Bible actually does not support this theory. In fact, according to the Bible there is no spirit inside of us at all. We exist only as mortal bodies, made from dust having been given the breath of life. And it is this “breath of life” that is confused with, or interpreted as, a “spirit”.
There are problems with your proposition.
1. As believers we are born of the Spirit. This birth is a creation of something new, that was not there before.
So it is with everyone born of the Spirit John 3:8
2. Jesus spoke to Elijah and Moses. Now the resurrection has not happened yet but here they are.
And there appeared before them Elijah and Moses, who were talking with Jesus Mark 9:4
3. In revelation the souls of the dead call out
I saw under the altar the souls of those who had been slain because of the word of God and the testimony they had maintained.
Rev 6:9
4. The thief on the cross is given a promise
Jesus answered him, "I tell you the truth,
today you will be with me in
paradise." Luke 23:44
5. We are body and soul. If it were not so, our souls could not be destroyed because they did not exist.
Do not be afraid of those who kill the body but cannot kill the soul. Rather, be afraid of the One who can destroy both soul and body in hell.
Matt 10:28
6. Paul describes us as spirit, soul and body
May your whole
spirit,
soul and body be kept blameless at the coming of our Lord Jesus Christ. 1 Thess 5:23
7. God commands us to
Love the LORD your God with all your heart and with all your soul and with all your strength. Deut 6:5
8. Scripture divides our soul and spirit.
For the word of God is living and active. Sharper than any double--edged sword, it penetrates even to dividing
soul and
spirit, joints and marrow; it judges the thoughts and attitudes of the heart. Heb 4:12
Our soul and spirit are expressed through our physical bodies. The question is, is our souls and spirits locked as an attribute of our bodies or as a part of being a living being.
Jesus is described as Gods word, His message, His speaking forth, and finds physical form as a man.
If Jesus has a separate spirit as a human, from the Holy Spirit, we have a problem in identity.
If the term spirit is an expression of our expression or mood, soul is the expression of our presence, and heart is an expression of our fundamental reality of who we are without defence or protection, then these are expressions of our being created.
Samuel was brought back from the dead to talk to Saul, and not in physical form.
Samuel said to Saul, "Why have you disturbed me by bringing me up?I am in great distress," 1 Sam 28:15
All these question relate to what is reality, and what are we and how do we mortals relate too immortality.
We are not spirits without a body, so our link to our physical bodies is very real. But we make a mistake to
think our physical existence is any more substantial, because we experience things this way.