Man is made in the image and likeness of God. 
A three part being; soul, spirit and body.

For the word of God is quick, and powerful, and sharper than any two-edged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart Hebrews 4:12.

In the Old Testament, when the people of Israel wanted to offer themselves in full sacrifice to God, they sacrificed a pigeon.
Now, because of Jesus' sacrifice, we offer ourselves to God.

Man was not suppose to eat from the Tree of Knowledge of Good and Evil for the development of the soul, but from the Tree of Life for the development of the spirit.

Spiritual Christians do not live in the soul realm,
they live in the spirit realm Romans 8:11.

Worldly people are sinners and function only in body and soul.
Soulish Christians live and are motivated by their bodies and souls.

The Holy Spirit comes into our spirit.
But if the Spirit of Him that raised up Jesus from the dead dwell in you, He that raised up Christ from the dead shall also quicken your mortal bodies by His Spirit that dwelleth in you. 
Romans 8:11

Our dead spirit must be born of the Spirit of God.
Jesus said that except a man be born of the Spirit, 
he cannot enter into the kingdom of God, John 3:5.

When we are born into this world as children, 
our spirit is dead to God as in John 3:3-7.

Our body is and always has been the servant and slave of the 5 senses: 
touch, taste, smell, hearing and sight.

Proverbs 20:27 The spirit of man is the candle of the LORD,
searching all the inward parts of the belly.

Our body is our flesh, blood and bones.

Our soul is our mind, will and emotions.

Our spirit is our conscience, fellowship with God and intuition.

We humans are made up of 3 parts: spirit, soul and body.

By walking in God's love, His holiness, and His righteousness; 
a disciple of Christ doesn't walk in darkness, in sin or in rebellion.

Paul said in Galatians 5:16 "This I say then, 
walk in the Spirit and ye shall not fulfill the lust of the flesh."

If Christians do not know the difference between soul and spirit; 
they will likely live in the soul realm [the lower life] and not in the spirit realm [the higher life].

The born-again believer must have a biblical understanding of 
the soul and spirit because only by the spirit can man know spiritual reality.

In the new life of the last Adam, Jesus, we learn how to battle 
the devil successfully. Ephesians 6:10-18

In what is spirit and what is soul, 
we face the old and new creations.
"For as in Adam all die, even so in Christ shall all be made alive."
1 Corinthians 15:22

It is greatly important for spiritual health of individuals and the church 
to know the difference between soul and spirit. 
Otherwise they cannot know what is spiritual or what is carnal.

We, as Christians, need a clear understanding 
to be able the tell the difference 
what is spirit and what is soul as individuals.

Psalm 8:4-6 What is man, that thou art mindful of him? 
and the son of man, that thou visitest him?
For thou hast made him a little lower than the angels, 
and hast crowned him with glory and honour.
Thou madest him to have dominion over the works of thy hands; thou hast put all things under his feet:

Salvation is in 3-parts.
1 John 5:8 And there are three that bear witness in earth, 
the Spirit, and the water, and the blood: 
and these three agree in one.

Man was created a 3-part being.
1 Thessalonians 5:23  And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.