Why I Believe Struggling Against Sin is a Fruit of Genuine Christianity

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There are many times that I doubt if I'm even saved. I can remember listening to some of Paul David Washer's sermons. As much as he was preaching against false conversions but he also emphasized the sad truth that Christians do still sin but aren't proud of it. Can Christians be carnal? Yes. But can a Christian be carnal indefinitely? Then that answer is a no. It's very easy to take Romans 7:14-25 but let's see what it really says:
Romans 7:14-25 
For we know that the law is spiritual: but I am carnal, sold under sin. For that which I do I allow not: for what I would, that do I not; but what I hate, that do I. If then I do that which I would not, I consent unto the law that it is good. Now then it is no more I that do it, but sin that dwelleth in me. For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. For the good that I would I do not: but the evil which I would not, that I do. Now if I do that I would not, it is no more I that do it, but sin that dwelleth in me. I find then a law, that, when I would do good, evil is present with me. For I delight in the law of God after the inward man: but I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members. O wretched man that I am! who shall deliver me from the body of this death? I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin.

Here's a very meaningful quote by Arthur W. Pink:
STRUGGLE WITH SIN – A HEALTHY SIGN 
"He who is really honest with himself and has had his eyes opened in some degree to see the awful sinfulness of self, and who... is becoming more and more acquainted with that sink of iniquity, that mass of corruption which still indwells him, often feels that sin more completely rules him now than ever it did before. When he longs to trust God with all his heart, unbelief seems to paralyze him. When he wishes to be completely surrendered to God’s blessed will, murmurings and rebellion surge within him.  
When he would spend an hour in meditating on the things of God, evil imaginations harass him. When he desires to be more humble, pride seeks to fill him. When he would pray, his mind wanders. The more he fights against these sins, the further off victory seems to be. To him it appears that sin is very much the master of him, and Satan tells him that his profession is vain. What shall we say to such a dear soul who is deeply exercised over this problem? 
The very fact that you are conscious of these sins and are so much concerned over your failure to overcome them, is a HEALTHY SIGN. It is the blind who cannot see; it is the dead who feel not – true alike naturally and spiritually. Only they who have been quickened into newness of life are capable OF REAL SORROW FOR SIN. Moreover, such experiences as we have mentioned above evidence a spiritual growth: a growth in the knowledge of self. As the wise man tells us, ‘he that increaseth knowledge increaseth sorrow’ (Eccl. 1:18). In God’s light we see light (Ps. 36:9). The more the Holy Spirit reveals to me the high claims of God’s holiness, the more I discover how far short I come of meeting them. 
Let the midday sun shine into a darkened room, and dust and dirt which before were invisible are now plainly seen. So with the Christian: the more the light of God enters his heart, the more he discovers the spiritual filth which dwells there. Beloved brother, or sister, it is not that you are becoming more sinful, but that GOD IS NOW GIVING YOU A CLEARER AND FULLER SIGHT OF YOUR SINFULNESS. Praise Him for it, for the eyes of the vast majority of your fellows (religionists included) are blind, and cannot see what so distresses YOU!" 
~ Arthur Pink, "Studies on Saving Faith"

Just reading that quote I see myself in it. I read the Bible and I see my fleshly nature trying to compete with my spiritual nature. I want to think good but I also think bad. I just couldn't see how sinful I was until God gave me a clearer sight of my sinfulness. I don't even feel proud of doing sin and I can't even claim my power against sin by myself. Alone, I have no real power against sin. I am tempted to think of myself higher than others. I am tempted to get even with people who hurt me. But at the same time the new man wants to forgive. It's a real painful struggle and it happens everyday.

Where is the difference with the struggle against sin vs. me being enslaved to sin? Enslaved to sin means I find pleasure in sinning. If I think I can sin all I want because I'm saved by grace then I don't know what grace is. True grace leads to righteous living. If a person is truly saved by grace then by all means that person should have a different view by now.
1 Corinthians 15:10 
But by the grace of God I am what I am: and his grace which was bestowed upon me was not in vain; but I laboured more abundantly than they all: yet not I, but the grace of God which was with me.
Ephesians 2:8-10 
For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. For we are His workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.
Titus 2:11-14 
For the grace of God that bringeth salvation hath appeared to all men, teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly, in this present world; looking for that blessed hope, and the glorious appearing of the great God and our Saviour Jesus Christ; Who gave Himself for us, that He might redeem us from all iniquity, and purify unto Himself a peculiar people, zealous of good works.

Should it be mentioned that while salvation is by faith alone but this faith is never alone? True salvation results to good works. The idea wasn't invented by Martin Luther or Charles H. Spurgeon. Rather, it has been emphasized by the Bible. Luther once called James an epistle of straw until he fully understood what it meant.
James 2:14-26 
What doth it profit, my brethren, though a man say he hath faith, and have not works? Can faith save him? If a brother or sister be naked, and destitute of daily food, and one of you say unto them, Depart in peace, be ye warmed and filled; notwithstanding ye give them not those things which are needful to the body; what doth it profit? Even so faith, if it hath not works, is dead, being alone. Yea, a man may say, Thou hast faith, and I have works: shew me thy faith without thy works, and I will shew thee my faith by my works. Thou believest that there is one God; thou doest well: the devils also believe, and tremble. But wilt thou know, O vain man, that faith without works is dead? Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar? Seest thou how faith wrought with his works, and by works was faith made perfect? 23 And the scripture was fulfilled which saith, Abraham believed God, and it was imputed unto him for righteousness: and he was called the Friend of God. Ye see then how that by works a man is justified, and not by faith only. Likewise also was not Rahab the harlot justified by works, when she had received the messengers, and had sent them out another way? For as the body without the spirit is dead, so faith without works is dead also. 

If your faith is authentic then it should result to good works. Good works don't save anyone but they certainly manifest from being truly saved. One can say that anybody can do good works but Hebrews 9:12 calls them dead works. True salvation is salvation from the power of sin. Salvation means I got saved and I remain saved. I remain saved because I'm saved daily. Because I remain saved and I can't lose my salvation means that I will continue to grow in holiness as a result. Those who think that they're once saved, always saved but live in sin are well-deceived. My salvation from sin isn't complete yet but one day I will be inevitably and completely saved from all my sins. That's what it means to work out my salvation with fear and trembling by the grace of God.

True faith is not instantaneous but it grows. If any faith is genuine that it will endure testing. True gold endures and the dross is removed from the fire. True diamonds survive cutting and polishing. True branches survive the pruning while false branches don't (John 15:1-8). If your faith is real then there's going to be a struggle against sin. This is going to be where one can only say, "Lord help me, save me from sin." and not "Lord deliver me so I may sin some more." True faith will never be inclined to a life of sin but a life of good works. Since this faith is not yet perfected then sin appears but when a true believer sins they find no pleasure in it.

Having a doubt about your salvation? The Bible says you must examine yourself (2 Corinthians 13:5). That means it's time to do some checking. It's time to ask questions like do you love sin or do you want t get rid of sin. It's time see whether or not Jesus Christ is the Lord of your life and are you submitting yourself to Him? If sin pleases you and there's no remorse then Jesus is not first place in your life. If you sinned or you backslid which made you miserable it's only because Jesus is the Lord of your life and not you yourself. Only people who are lords over themselves instead of Jesus as the Lord of their lives will love sin. True salvation yields to the Lordship of Christ from salvation to sanctification and forever in glorification.

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