The introduction of sin into the world necessitated the constitution of things as they were laid in the beginning. If there had been no sin there would have been no "enmity" between God and man; and consequently no antagonism by which to educe good out of evil. Sin and evil are as cause and effect. God is the author of evil, but not of sin; for the evil is the punishment of sin. "I form the light, and create darkness; I make peace, and create evil; I the Lord do all these things" (Isaiah 45:7), "Shall there be evil in a city and the Lord hath not done it" (Amos 3:6)? The evil then to which man is subjected is the Lord's doing. War famine, pestilence, flood, earthquake, disease, and death, are the terrible evils which God inflicts upon mankind for their transgressions. Nations cannot go to war when they please, any more than they can shake the earth at their will and pleasure; neither can they preserve peace, when He proclaims war. Evil is the artillery with which He combats the enemies of His law, and of His saints; consequently, there will be neither peace nor blessedness for the nations, until sin is put down, His people avenged, and truth and righteousness be established in the earth.
This is the constituted order of things. It is the constitution of the world; and as the world is sin's dominion, or the kingdom of the adversary, it is the constitution of the kingdom of sin.
The word sin is used in two principal acceptations in the Scripture. It signifies in the first place, "the transgression of law;" and in the next, it represents that physical principle of the animal nature, which is the cause of all its diseases, death, and resolution into dust. It is that in the flesh "which has the power of death," and it is called sin, because the development, or fixation of this evil in the flesh was the result of transgression. Inasmuch as this evil principle pervades every part of the flesh, the animal nature is styled "sinful flesh," that is, flesh full of sin; so that sin, in the sacred style, came to stand for the substance called man. In human flesh "dwells no good thing" (Rom. 7:18-17); and all the evil a man does is the result of this principle dwelling in him. Operating upon the brain, it excites the "propensities," and these set the "intellect" and sentiments" to work. The propensities are blind, and so are the intellect and sentiments in a purely natural state; when, therefore, the latter operate under the sole impulse of the propensities, "the understanding is darkened through ignorance, because of the blindness of the heart" (Eph. 4:18).
(by Dr. John Thomas)