Pig is Pig and Flesh is Flesh! from 'If I Perish, I Perish' by Major Ian Thomas:
"It is absolutely imperative for your own spiritual well- being that you recognize the fact that this old nature will never change its character. All the wickedness of which it is capable today, it will be capable of tomorrow - or for that matter fifty years from now. The flesh within you then will be as wicked as the flesh within you today, and there is absolutely no salvageable content within it. What a relief it must be for you to discover that in all your attempts to harness the flesh in the service of Jesus Christ, and in all your painful endeavors to introduce it to godly principles of life and conduct, God has never expected anything of you but the hopeless failure you have been! You have been trying to do the impossible!
Imagine, if you will, that I have come to the conclusion that the pig as a species has been grossly misjudged; that the idea that a pig wallows in the muck by choice, and that by nature it loves the dirt, is wholly unfounded.
I have become fully persuaded that it is a question purely of environment, education and upbringing! I decide, therefore, to adopt a little baby pig into the family, and in this way prove my point by offering to it those amenities of life which will enable the best side of its character to be developed... We give the little pig a pink satin shirt and some little blue velvet pants, with ivory buttons down the sides. We teach it to wipe its feet when it comes into the house, to sit up at the table, to bow its head when we say grace, and to sleep at night between the sheets and the blankets with which we provide it, in its own little bed... It becomes quite obvious to us that it is only a matter of time before our endeavors are crowned with success. Unfortunately, it is just at this juncture, when our hopes are running high, that we make one fatal blunder. Somebody leaves the door open that leads into the grounds! Fresh breezes blow into the room where the little pig is playing. Sensing the fragrance of new-mown hay; the little pig's nose begins to twitch. Stopping halfway across the room it gazes out in the park - its curly tail unwinds and shoots straight up, stiff as a rod - like an aerial! There is a moment of hesitation, and then suddenly - like a bullet from a gun - the little pig races out through the open door and across the park, moving at incredible speed! Reaching the muddiest bog it can find, the little pig plunges in, and after rolling over and over, it lies on its back in the mud, little blue pants and all. With a delightful grin on its face, and with its feet sticking up in the air, it cries at the top of its voice - "Home, sweet home!"
You see, change its environment as you will, and train it as you may - little pink pants or blue, satin shirt or clean straw - Pig Is Pig! Given half a chance, the nature of the beast is to get back to where it belongs, and this you have found to be true in your own experience. The flesh within you has never ceased to love sin, and never will. Given half a chance it, too, will want to get back to where it belongs and wallow in the muck! This is why the godliest of men still have latent within them the most terrible potential for evil. It is the godliest of men who know it best, for it is the acknowledgment of this very fact which is the secret of their godliness. They have learned long since, and often by bitter experience, that character does not change for the better by improving the flesh, but by allowing it to be replaced by the Holy Spirit - for pig is pig! Only the Holy Spirit can render its pernicious appetites inoperative."
I tried so hard to "improve" my flesh. That's really what I had been doing all along; for years. Christ's ways are not a "self-improvement plan". Now, I acknowledge my sin, confess and repent on that and ask the Lord to forgive that. Move on.
Yet, we still sin, but as Paul says; "I have been crucified with Christ and I no longer live, but Christ lives in me. The life I now live in the body, I live by faith in the Son of God, who loved me and gave himself for me." and "As it is, it is no longer I myself who do it, but it is sin living in me."