Amplified So then those who are living the life of the flesh [catering to the appetites and impulses of their carnal nature] cannot please or satisfy God, or be acceptable to Him. (Amplified Bible - Lockman)

Barclay: Those whose life is a purely worldly thing cannot please God. (Westminster Press)

KJV: So then they that are in the flesh cannot please God.

NLT: That's why those who are still under the control of their sinful nature can never please God. (NLT - Tyndale House)

Phillips: Men who hold this attitude cannot possibly please God. (Phillips: Touchstone)

Wuest: Moreover, those who are in the sphere of the sinful nature are not able to please God. 

Young's Literal: for neither is it able; and those who are in the flesh are not able to please God.

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1.  Those in the flesh are identified as the lost.  They cannot please God.

2.  We as Christians can get in the flesh.  In that state, we cannot please God because we are acting religiously or immorally [both void of God's life]

Remember:  "flesh" is the fallen human nature from God.  It is a nature that runs away from God and His ways.  It destroys harmony.  It will not turn to  cooperate with God.  

It is visible as  "self-first", the "me",  the "I" focus for attention and gratification.  It feels "wronged" when not seen and recognized.  It reacts when not gotten what it desired. It seeks recognition, elevation, reward, and even pity.  It wallows in its feelings with no pursuit of truth how to properly respond with the use of the will.  Self, though self-willed to follow flesh, has, over time weakened the will to resist its feelings and desires.

Example:  It is offended and reacts to not being recognized, honored, thanked, etc.  It doesn't feel honored.

Self feels this way.  Though every Christian feels this way at times, this feeling must be led to the cross.  We may suffer what we feel and endure what we think.  But we must look to Christ for help denying sin, holding our tongue, and offering words that edify.