Your spirit is the real you.  In the Bible, Paul uses the terms "my spirit" and "I" interchangeably.
Your heart is your spirit.  The words "heart" and "spirit" are used interchangeably in the Bible.
(This is not talking about our physical heart organ.  It's about the love we feel in our heart/spirit.)
1Pe 3:4  But let it be the hidden man of the heart [spirit] [the inward man] [the eternal man], in that which is not corruptible, even the ornament of a meek and quiet spirit, which is in the sight of God of great price.
2Co 4:16  ...Though our outward [physical] man perish [is decaying], yet the inward man is renewed day by day [is eternal].  2Co 4:17-18  ...for the [physical] things which are seen are temporal; but the things which are not seen are eternal.  The only way we can look at the unseen is by faith.

There can be all kinds of doubts in our (soul's) mind, but we can believe in our heart/spirit.
Mar 11:24  ... What things soever ye desire, when ye pray, believe that ye receive them, and ye shall have them.

Jesus was God manifested in the flesh:
Joh  1:1-3,14  ... And the Word was made flesh, and dwelt among us ....

Ezekiel was prophesying concerning the new birth in Eze 36:26-27.
The new birth is a rebirth of the human spirit
When a man is born again, the spirit (which is the real man) is born again, and the old spirit  man is gone.  However, our physical body is not replaced until Christ returns.
When we are born again, we receive the gift of eternal life.
Rom 6:23  For the wages of sin is death; but the gift of God is eternal life ....
When eternal life, which is the nature and the life of God, is imparted to your spirit, it changes you.  This life of God, coming into your heart, makes your inward man (the real you) a new man.
2Co 5:17  Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
After we are born again, we will still have trouble with the flesh (physical, body), but we won't have trouble with the real man.

We will have a new body one day, but we have the new life right now.
Joh 10:10  ... I [Jesus] am come that they might have life, and that they might have it more abundantly.

God's nature is love.  Therefore, if a man is born again, he will be filled with God's love.
Joh 13:35  By this shall all men know that ye are my disciples, if ye have love one to another.

After being born again (saved) and baptized in water; in a later, separate event, the Holy Spirit will come to dwell in us as Comforter, Helper, and Guide.
ACT 8:15-17  Who, when they were come down, prayed for them, that they might receive the Holy Ghost:  (For as yet he was fallen upon none of them: only they were baptized in the name of the Lord Jesus.)  Then laid they their hands on them, and they received the Holy Ghost.
Once the Holy Spirit comes,  Joh 14:16  ... he abides with you for ever.
The Holy Spirit speakes to our spirit, often as we read the Bible.

Most people function primarily out of their soulish realm, believing what they think and feel is reality.
It is easy to think we are listening to God in spirit, when in fact, we are only listening to our mind, which has reached intellectual conclusions based on our physical senses, and worldly limitations.

If you're dominated by what you feel, your soul is agreeing with the natural realm.  "I feel sick and my body hurts.  The doctor said I'm dying.  Here's my medical record to prove it!"  Your soul can choose to block or ignore information that could be flowing from your spirit.  You're saying "Something's just not real if it can't be perceived through my five natural senses, or does not comply with known worldly limitations and constraints."

When your soul agrees with your spirit, the life of God in you will manifest itself in your physical body.  You'll experience healing, deliverance, anointing, victory, power, joy, prosperity, etc.  Once your soul believes God's promises, then His promise becomes "reality" to you, even before you physically have or experience it, because you know God keeps His promises.

[ Note:  A few sentences above have been adapted from a book entitled "Spirit, Soul & Body" written by Andrew Wommack [AW] in 2005.  The complete book is available from:  www.awmi.net ]

We want to make our belief in God's Word more than just mental assent.
Mental assent agrees that the Bible is true, but doesn't act on it.  (Mental assent says, "I know God's Word is true all right.  I know God promised me certain things, and I ought to have them.")

Real faith is acting on God's word.  Faith sees the object of prayer as already having been attained.  (Faith says, "The word of God (the Bible) says it, I believe it, and I have it now," even though it may not be seen in the natural.  Faith says, "I have it now --, not because I can see it, not because I actually possess it, but because God promised it.")
Heb 11:1  Now faith is the substance of [Faith is giving substance to] things hoped for, the evidence of things not seen.
Our faith gives substance to it, and we can say, "It is mine."

God expects us to have control over our bodies, and not let them dominate us.
Body-ruled Christians, remain baby Christians, until they become Spirit-ruled.
1Co 9:27  But I [the inward man] keep under my body [the outward man], and bring it [the outward man] into subjection [to the inward man] ....