Apostle Paul wrote, "This I say then, Walk in the Spirit, and ye shall not fulfill the lust of the flesh.  For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.  But if ye be led of the Spirit, ye are not under the law" (Galatians 5:16-18).

These Scriptures must not be taken out of context.  They in no way imply that a believer is a helpless victim of the flesh and unable to walk victorious before God.  However, they do describe the unacceptable condition of which the Galatians had regressed into, by searching for eternal life through their own carnal flesh and selfish individual efforts.  Apostle Paul reveals in Galatians 5:19-26 what the fruits of a born again believer are verses the works of a non believing sinner.

Apostle Paul makes his argument for victorious Christian living by revealing that, "Knowing this, that our old man is crucified with him, (Yeshua) that the body of sin might be destroyed, that henceforth we should not serve sin.  For he that is dead is free from sin.  Now if we be dead with Christ, we believe that we shall also live with him: Knowing that Christ being raised from the dead dieth no more; death hath no more dominion over him.  For in that he died, he died unto sin once: but in that he liveth, he liveth unto God.  Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord. 

Let no sin therefore reign in your mortal body, that ye should obey it in the lusts thereof.  Neither yield ye your members as instruments of unrighteousness unto sin: but yield yourselves unto God, as those that are alive from the dead, and your members as instruments of righteousness unto God ... But God be thanked, that ye were the servants of sin, but ye have obeyed from the heart that form of doctrine which was delivered unto you.  Being made free from sin, ye became the servants of righteousness..." (Romans 6:6-23).       

Although, it should be noted that a believer will have war with his/her flesh on many different occasions but will always have the weapons of victory (Holy Spirit) as long as they are actively pursuing God's Word.  When Apostle Paul was teaching the Corinthians how to vigorously pursue eternal life, he stated, "Know ye not that they which run in a race run all, but one receiveth the price?  So run, that ye may obtain.  And every man that striveth for the mastery is temperate in all things.  Now they do it to obtain a corruptible crown; but we an incorruptible.  I therefore so run, not as uncertainly; so fight I, not as one that beateth the air: But I keep under my body, and bring it into subjection; lest that by any means, when I have preached to others, I myself should be a castaway" (I Corinthians 9:24-27).

Apostle Paul made it very clear the power that was made available to the believer when walking in the Spirit, "For though we walk in the flesh, we do not war after the flesh: (For our weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds;) Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ" (II Corinthians 10:3-5).