But, as we know, Adam was induced to take the second source, the tree of knowledge, into himself. This was not a matter of merely doing something wrong. No! It was much more serious than transgressing God’s law and regulation. The significance of Adam taking the fruit of the tree of knowledge was that he received Satan into himself. Adam did not take the branch of that tree, he took the fruit of the tree. The fruit contains the reproducing power of life. For example, when the fruit of a peach tree is planted in the earth, soon another little peach tree will sprout up. Adam was the "earth." When he took the fruit of the tree of knowledge into himself as the earth, he received Satan, who then grew in him. Oh, this is not a small matter! Not many Christians have realized the fall of Adam in such a way. The fruit of Satan was sown in Adam as a seed in the soil; thus, Satan grew in Adam and became a part of him.
Now we need to discover into what part of Adam Satan was taken. Satan not only came into Adam when he fell in the garden, but he still remains in the human race. Where is he located in the human race? We are a tripartite being: spirit, soul, and body. Look at the picture. When Adam took the fruit of the tree, into what part of his being did it come? Of course, it came into his body, because he ate it. Although this is logical and reasonable, we need scriptural ground to confirm that something of Satan is in our body. Read Romans 7:23: "But I see a different law in my members, warring against the law of my mind." The word "another," in the King James Version, is not a good translation. It should be "a different law"—i.e., a law of a different category. You may have three laws of the same category, e.g., the first, and "another" two. But the Greek here means a law of a contrasting category. "But I see a different law in my members [the members are the parts of the body], warring against the law of my mind, and making me a captive in the law of sin which is in my members," that is, the parts of the body.
What is the law of sin? Paul said, "...no longer I...but sin that dwells in me" (Rom. 7:20), and, "...no longer I...but Christ lives in me" (Gal. 2:20). Here we have the contrast between "no longer I...but sin," and "no longer I...but Christ." Christ is the embodiment of God, but sin is the embodiment of Satan. The word "sin" in Romans 7 should be capitalized, for it is personified. It is like a person, for Sin can dwell in us and force us to do things against our will (Rom. 7:17, 20). It is even stronger than us. Romans 6:14 says: "For sin shall not have dominion over you." It is better to translate it: "For Sin shall not have the lordship over you," or, "for Sin shall not be lord over you." Sin can be lord over us; hence, Sin must be the evil one, Satan. Through the fall, Satan came into man as Sin, and is ruling, damaging, corrupting and mastering him. In what part? Satan is in the members of man’s body.
Man’s body as originally created by God was something very good, but it has now become the flesh. The body was pure, since it was created good, but when the body was corrupted by Satan, it became flesh. Paul said, "...in me, that is in my flesh, nothing good dwells" (Rom. 7:18). By the fall, Satan came to dwell in our body, causing our body to become flesh—i.e., a damaged, ruined body.
The book of Romans uses two terms, "the body of sin" (6:6) and "the body of this death" (7:24). The body is called "the body of sin" because Sin is in the body. The body simply became the residence of Sin, which is the embodiment of Satan. What, then, is "the body of this death"? The source and power of death is Satan. Sin is the embodiment of Satan and death is the issue or effect of Satan. This corrupted, transmuted body is called the "body of sin," and the "body of this death," because this body became the very residence of Satan. Both sin and death are related to Satan. "The body of sin" means that the body is sinful, corrupted and enslaved by Sin; "the body of this death" means that the body is weakened and full of death. The body is something satanic and devilish, because Satan dwells in this body. All the lusts are in this corrupted body which is called the flesh. The Word reveals that the lust is "the lust of the flesh" (Gal. 5:16). The flesh is the corrupted body full of lusts, indwelt by Satan. Now you see that the fall of man was not just a matter of man committing something against God, but of man receiving Satan into his body. Satan, from the time of the fall, dwells in man. This is what happened when man partook of the second tree.
Since Satan and man became one through the second tree, Satan is no longer outside of man, but in man. The prince of the air, Satan himself, is working in the disobedient people (Eph. 2:2). Satan was joyful, boasting that he had succeeded in taking over man. But God, who was still outside of man, seemed to say: "I will also become incarnated. If Satan wrought himself into man, then let Me enter man and put man upon Myself." Do you see the complicated situation? God put on this man—Satan being in him—through incarnation. When God became incarnated as a man, the kind of man He put on was a man corrupted by Satan. Man, at the time of His incarnation, was no longer a pure man, but a man ruined, corrupted by Satan. Let us read Romans 8:3: "God, sending His own Son in the likeness of the flesh of sin"—not "sinful flesh," as in the King James Version, but "the flesh of sin." When the Lord Jesus incarnated Himself in flesh, He was "in the likeness of the flesh of sin." There was no sin within Him, but there was "the likeness of the flesh of sin." Sin was within the corrupted man, but there was no sin within the Lord Jesus; there was only the likeness of the flesh of sin. The Old Testament illustrates this in the type of the brass serpent on the pole. That serpent, made of brass, was a type of Christ (John 3:14). When Christ was on the cross, He was a man in "the likeness" of the serpent. The serpent is Satan, the devil, the enemy of God, but when Christ was incarnated as a man, He had even the likeness of the sinful flesh, which is the likeness of Satan. It is rather difficult for anyone to understand this easily. It is really quite complicated. Let me repeat. Man was made pure, but one day Satan came into man to possess him. Satan was joyful, thinking he had succeeded in taking over man. Then God put upon Himself the man with Satan within him.
(Man and the Two Trees, Chapter 1, by Witness Lee)