The soul is the personality part of our being. The spirit is the entity that lives forever and dwells in the body as long as it is on earth.
When our body dies our spirit goes to heaven or hell. Our personality remains with our spirit and is taken to whichever place we go. The body is only dust nothing else, it is the shell or casing that holds our spirit with its personality.
When someone becomes born again their spirit is replaced with the Spirit of Christ. This is why we are referred to as a "new creation" when Christ changes us into His children, we are sealed with the Holy Spirit of Promise until He takes us out of this world.
Job 32:8
But it is the spirit in man, the breath of the Almighty, that makes him understand.
Ecclesiastes
And the dust returns to the earth as it was, and the spirit returns to God who gave it.
Romans 8:16
The Spirit himself bears witness with our spirit that we are children of God,
Romans 8:8-10 "Those controlled by the flesh cannot please God. 9 You, however, are controlled not by the flesh, but by the Spirit, if the Spirit of God lives in you. And if anyone does not have the Spirit of Christ, he does not belong to Christ. 10 But if Christ is in you, your body is dead because of sin, yet your spirit is alive because of righteousness.…"
