We are always so quick to say, "I can't understand how he/she could have done ___________. Is that the way a true Christian would act?" When we should be saying, "There but for the grace of God go I."
Scripture reminds us that, "Pride goes before destruction, and a haughty spirit before stumbling." (Proverbs 16:18), and "For I know that nothing good dwells in me, that is, in my flesh; for the willing is present in me, but the doing of the good is not" (Rom 7:18).
And in Romans 1:28 it says that God gave man over to a depraved mind.
The worldly mind knows well how to lie, cheat, steal, gossip; it perverts everything it thinks about. The shocking truth is when we become Christians, this worldly mind still exists and continually harasses our new mind (in Christ). The difference is we now have a choice. We can choose to "put on the new man" (Eph 4:24; Col 3:10). And when our new nature is in control, we think as Christ thinks.
Have this attitude in yourselves which was also in Christ Jesus (Phil 2:5).
On the other hand, if our old nature is allowed to be in control, we are capable of anything.
For what I am doing, I do not understand; for I am not practicing what I would like to do, but I am doing the very thing I hate. But if I do the very thing I do not want to do, I agree with the Law, confessing that the Law is good. So now, no longer am I the one doing it, but sin which dwells in me. For I know that nothing good dwells in me, that is, in my flesh; for the willing is present in me, but the doing of the good is not. For the good that I want, I do not do, but I practice the very evil that I do not want. But if I am doing the very thing I do not want, I am no longer the one doing it, but sin which dwells in me. I find then the principle that evil is present in me, the one who wants to do good. For I joyfully concur with the law of God in the inner man, but I see a different law in the members of my body, waging war against the law of my mind and making me a prisoner of the law of sin which is in my members. Wretched man that I am! Who will set me free from the body of this death? Thanks be to God through Jesus Christ our Lord! So then, on the one hand I myself with my mind am serving the law of God, but on the other, with my flesh the law of sin (Rom 7:15-25).
Indeed, there is a battle waging within us---a battle between our old and new natures. From the moment of our salvation, our "new man" and "old man" aggressively compete for possession of our mind, emotions, and body. But we need not be defeated, thinking, "What's the use? No matter how hard I try, I'm bound to fail anyway." There's the mistake right there---relying on the "trying." Because no matter how hard we try to alter our old nature, we cannot change it. For when a person receives Christ, the “old man” is not cleaned up. After all, it is dead!
If Christ is in you, though the body is dead because of sin, yet the spirit is alive because of righteousness (Rom 8:10).
For you have died and your life is hidden with Christ in God (Col 3:3).
Rather, a new creation is instantly given.
Knowing this, that our old self was crucified with Him, in order that our body of sin might be done away with, so that we would no longer be slaves to sin (Rom 6:6).
But, spiritual growth is needed to strengthen the “new man” in this war. And there is no growth without Bible study and prayer (Eph 1:16-18; Col 3:16).
A relationship with a local assembly of believers is also essential to growth, "…encouraging one another; and all the more as you see the day drawing near” (Heb. 10:25).
Therefore, the key to living a successful Christian life is considering our old nature dead (keep it in its coffin!) and letting our new nature rule in its place, drawing on the power of the Holy Spirit.
No, I'm certainly not better than the next guy---I often fail! But as I grow in Christ, I can experience His victory over my sinfulness more and more often.
Two natures beat within my breast.
One is foul, the other blest.
The one I love; the one I hate.
The one I feed will dominate. (Author unknown)