What is the origin of the self? Since God did not create the self, where did the self come from? In order to answer the question concerning the origin of the self, it would be helpful to consider the difference between the body and the flesh.
God created for man a body that was good, pure, and sinless. The flesh is also the body, but it is the corrupted, ruined body. Satan injected sin into the human body created by God, and in this way the body was corrupted and ruined, becoming the flesh. The flesh, therefore, is the body corrupted by sin. We may also say that the flesh is the body plus sin.
The sin which is in man's body is the very nature of Satan. In Romans 6 and 7 sin is personified, for it is likened to a living person that dwells in us (7:17, 20), works in us (v. 8), deceives us (v. 11), kills us (v. 11), and reigns in us (6:12, 14). This sin which, like a living person, can force us to do things against our will, is the nature of Satan. We may even say that sin is Satan. Because sin has been injected into our body and is now in the members of our body, our body has been corrupted and has become the flesh.
The situation is similar with the self. The body became the flesh because something of Satan—sin—was injected into it. How did the soul become the self? The soul became the self when something of Satan was added to the soul. The thing that was added to the soul was the thought, or the mind, of Satan. Therefore, the self is the soul plus the satanic mind, the mind of Satan. When the mind, the thought, of Satan was injected into the human soul, the human soul was corrupted and became the self.
The body has been changed into the flesh, and the soul has been changed into the self. Which of these changes took place first? The answer to this question is found in Genesis 3:1-6. Here we see that before Eve took the fruit of the tree of the knowledge of good and evil into her body, the thought, the mind, of Satan was injected into her soul. Satan came to Eve with the intention of putting his thought into her mind. Satan did this when he said to her, "Yea, hath God said, Ye shall not eat of every tree of the garden?" (v. 1). This was an appeal to Eve's mind. Eve answered Satan (vv. 2-3), but as soon as she did so, she was "hooked" in her mind by the "bait" of Satan's thought.
Day after day Satan tries to do the same thing with us, sending some sweet, enticing bait to our mind. For instance, in the morning, as you are waking up, a critical thought concerning the church in Los Angeles may suddenly enter your mind. Such a thought is Satan's bait, and the more you pay attention to this bait, the more you will be hooked by Satan. Eventually, you may decide to give up the church life.
Satan did not come to Eve to fight with her or to speak against her. Rather, he came in a nice way to "help" her. In response to Satan's question, she said, "We may eat of the fruit of the trees of the garden: but of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die" (vv. 2-3). At this point Eve was already caught by Satan who, taking Eve's word as his basis, said to her, "Ye shall not surely die: for God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil" (vv. 4-5). Satan seemed to be saying to the woman, "I am here as your good friend to tell you a secret. God is fooling you. If you eat of the fruit of this tree, you will be like a god."
Through this satanic assault, Eve's mind was attacked. Then her mind was poisoned by the satanic thought which had been injected into her. After this, her emotion was aroused when she "saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise" (v. 6a). Next, her will was exercised to make a decision to eat of the fruit of the tree of the knowledge of good and evil. "She took of the fruit thereof, and did eat" (v. 6b). By this time every part of the soul—the mind, the emotion, and the will—had been poisoned.