Christian men must violently oppose selfishness wherever it may be found. Unchecked, unrealized, and undealt-with selfishness that is allowed to fester in one's life can indeed manifest in ways that once were unimaginable to the doer.
I think we can all relate to what Paul says in Romans 7: 15: "What I will to do, that I do not practice; but what I hate, that I do." During the writing of this, if someone asked me, "Would you like to watch pornography?" I would clearly and defiantly say no. Why then, countless times in my life, have I done that exact thing, and things of the like, and things even further steeped in darkness?
This is a puzzling question. I often talk of assiduity. Doing things on purpose, with purpose. But the rubber meets the road in the moment. While free of temptation to sin, we can conjure all day long about what we stand for, and our strength to chose rightly. But strength was made for the battle, and in fact only is strength if it is proven in the battle. That battle rages all around all day long, in waves and seasons, but it is unrelenting. Standing on the field, thinking back to past victories or defeats, we plan our actions. But the plan is said to be the first casualty in war, and when temptation hits once more, we are back to what Paul spoke of - doing that which we hate, and we previously professed to abstain from.
In reality, our own strength will never win the war. I alone am incapable of defeating any temptation that is thrown my way. I may for a season experience victories, and I may implement safeguards in my daily routine, but these only prolong an ongoing seige, they do not allow for a break into the offensive.
Romans 8: 13 says this, "For if you live according to the flesh you will die; but if by the Spirit you put to death the deeds of the body, you will live."
'By the Spirit' is the principle thing.
Now, seeking to put to death the deeds of the flesh by the Spirit can lead a man into two ditches, for there are always ditches on each side of a road. One ditch, is legalism. This would be seeking so fervently to conquer sin that faith turns from the Spirit's power to your own. The ditch on the other side of the road would be akin to passivity - the thought that the Spirit will enter you and move through you without any action of your own, simply requiring you to sit back and let life happen to you, whatever you do must be the work of the Spirit.
I have often attributed my failures to not hating my sin enough - there may be an element to this that is true. But regardless how deep my hatred of the dark, I am powerless on my own to fight the battle, my strength is carnal. The strength of the Spirit is heavenly, and so, we must pray. Yes we must hate sin, yes we must be strong and conduct ourselves as men, yes we must choose rightly, but we are powerless without the Spirit - This is my prayer.
"Holy Spirit, I cannot produce holiness apart from you. Help me walk by you today. Teach me to hate what you hate and love what you love. Produce your fruit in me, especially self-control. By your power, help me put to death the desires of my flesh today. Amen"
I began this post speaking of selfishness. Most Sin's that I can think of in my past are rooted in it. It is the putrid soil in which the weeds of various vile acts were first sprouted. It must be violently hunted in every area of a man's life, learning by the Spirit to hate what the Lord hates, and to love what the Lord loves.