Flesh vs. Spirit
The flesh can be said to be the part of man that is not renewed in God. It is the human soul (mind, will, and emotions) that is corrupted by sin. Whenever we see the flesh mentioned in scripture, it always alludes to sin and the sinful nature in man.
When we say that a man is in the spirit, we mean that his spirit (which was deadened by sin) has been renewed by God’s Spirit. It is the mind, body, and spirit of man that now has the Spirit of God guiding him. When the spirit of God comes into a man [through salvation], man begins to live by the spirit instead of living by the flesh.
We can see here that there are two ways of living. We can live according to the flesh, or we can live according to the spirit. When we live according to the flesh we will gratify the desires of the flesh which are guided by our sinful nature. But if we live by the spirit, we will gratify the desires of the spirit which are guided by the Holy Spirit living in us.
How do we know whether we are in the flesh or in the spirit?
By the fruit
Now the works of the flesh are evident: sexual immorality, impurity, sensuality, idolatry, sorcery, enmity, strife, jealousy, fits of anger, rivalries, dissensions, divisions, envy, drunkenness, orgies, and things like these. Galatians 5:19-21
But the fruit of the spirit is love, joy, peace. Patience, kindness, goodness, faithfulness, gentleness, self-control; against such things, there is no law. Galatians 5:22-23
In order for us to know whether we are living by the flesh or by the spirit, we have to look at the evidence of the fruit that is in our lives. Fruit is always consistent with the seed that has been planted.
Death and life
For to set the mind on the flesh is death, but to set the mind on the Spirit is life. Romans 8:6
When we choose to live according to the flesh we are choosing death. Because to live by the flesh is to live by our sinful nature which is death. And to live by the spirit is to live a life guided By His Spirit which results in life.
Both of these have a consequence as we can see in Romans 6:2 for the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.
Sin produces death in our lives while living by the spirit produces life- which is the gift of God to the believer.
Whatever is touched by sin in our lives will die, but whatever is influenced by the spirit will have life. Death and life is the clear indication whether something is of the flesh or of the Spirit.
The war between the two
Or the mind that is set on flesh is hostile to God, for it does not submit to God’s law. Romans 8:7
We cannot serve God in the flesh, it is impossible because the flesh by nature is hostile to God, it is against God’s laws.
Galatians 5:17 tells us for the desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh, for these are opposed to each other, to keep you from doing the things you want to do.
The flesh and the spirit can never mix as we see above. The two are in constant conflict with one another.
This can be explained by the struggle we often feel when we want to do the things of the spirit like praying, bible study, worship, obedience, and walking in love. The flesh will either keep us from doing these things or the spirit through continuous practice will overcome our flesh.
The flesh doesn’t want to pray. It doesn’t want to walk in love. It doesn’t want to forgive. It doesn’t want to worship God or walk in obedience to God.
I have learnt through experience that if I will constantly choose to walk in the spirit, with time it trains my mind and body to do the things of the spirit- almost out of habit- and weakens the power of the flesh in me to the point that my flesh will not dictate whether I walk in the spirit or not.
The flesh cannot please God
Those who are in the flesh cannot please God. Romans 8:8
As 1 Corinthians 2:14 explains so clearly, the person without the spirit does not accept the things that come from the spirit of God but considers them foolishness, and cannot understand them because they are discerned only through the spirit.
Amplified Translation says…For they are foolishness [absurd and illogical] to him.
This is why the flesh cannot please God. Faith is illogical and foolishness to the natural mind without the Spirit. Prayer, fasting, and worship are foolishness to the flesh. Loving our enemies, forgiving those who have hurt us, and being kind to those who are unkind to us is foolishness to the flesh.
How do we live by the spirit instead of the flesh?
But I say walk habitually in the [Holy] Spirit [ seek him and be responsive to His guidance], and then you will certainly not carry out the desire of the sinful nature [ which responds impulsively without regard for God and His precepts]. Galatians 5:16 AMP
It sounds quite simple but it is not. It is a fight to choose to walk by the spirit because the flesh wants to gratify its desires in us. But it is not impossible. I love how Amplified says to seek Him and be responsive to His guidance. This is the key to a spirit-led life, we seek God and respond to His guidance, and we will not walk or live by our flesh.
For if you are living according to the [ impulses of the] flesh, you are going to die. But if [ you are living] by the power of [ the Holy] Spirit you are habitually putting to death the sinful deeds of the body, you [ really] live forever. Romans 8:13 AMP
We habitually put to the flesh death through the help of the Holy Spirit. Don’t try to overcome your sinful nature through willpower, it’s futile, we can only do it by His power.
Habitually has the idea of doing something over and over again. It’s not a one-time thing- it’s a life of consistently dying to our flesh so we can live by the spirit. We have to deal with the flesh, it does not naturally go away just because we got born again. There has to be a work in every believer to bring to death his/her flesh in order to live by the spirit.
So put to death the sinful earthly things lurking within you. Have nothing to do with sexual immorality, impurity, lust, and evil desires. Don’t be greedy, for a greedy person is an idolater, worshipping the things of the world. Colossians 3:5 NLT
It’s repeated…Put to death! We intentionally deal with the flesh by putting it to death. It can be the most difficult thing because it requires us to die. We don’t want to die to sin because we have to kill ourselves in the process. It is a painful thing to bring one to death; this is why most people cannot deal with their flesh.
There has to be a crucifixion
We know that our old self [ our human nature without the Holyspirit] was nailed to the cross with Him, in order that our body of sin might be done away with so that we should no longer be slaves to sin. Romans 6:6
Some translations say…our old self was crucified with Him.
Ouch! Crucifixion is a painful and gruesome death. We have to understand the way God sees sin so we can know how to deal with it. We must go through a crucifixion so that we can be free to sin.
Through the cross, we have been empowered to do what we were unable to do before. Christ was crucified on our behalf that we might be able to die to the flesh.
Those who belong to Christ Jesus have crucified the flesh with its passions and desires. Galatians 5:24
God expects us to go through a crucifixion of the flesh to be able to live and walk by the spirit.
There is a putting away
To put off your old self, which belongs to your former manner of life which is being corrupted through deceitful desires. And to be renewed in the spirit of your minds. And to put on the new self, created after the likeness of God in true righteousness and holiness. Ephesians 4:22-24
This right here is the mark of a life in God-We put off the ways of the flesh, we then renew our minds and put on our new nature in Him, and begin to live by the spirit.