The nature and origin of evil has always been one of the most central questions of theology. So Berkhof in his systematic theology:
“It is a problem that naturally forces itself upon the attention of man, since the power of evil is both great and universal, is an ever present blight on life in all its manifestations, and is a matter of daily experience in the life of every man. Philosophers were constrained to face the problem and to seek an answer to the question as to the origin of all the evil, and particularly of the moral evil, that is in the world. To some it seemed to be so much a part of life itself that they sought the solution for it in the natural constitution of things. Others, however, were convinced that it had a voluntary origin, that is, that it originated in the free choice of man, either in the present or in some previous existence. These are much closer to the truth as it is revealed in the Word of God.”
He notes that Irenaeus is one of the earliest church writers to identify the origin of sin with Adam’s fall. The Church in general adopted this position as opposed to the Gnostics, who regarded matter to be the inherently evil result of a creator called the Demiurge. The human soul, according to them, became evil by its contact with matter. Origen accepted the eccentric position that humans sinned in a pre-bodily existence which explained why we enter the world sinful. This is obviously an unbiblical position that, fortunately, never caught on. Berkhof notes that the Greek Church Fathers of the 3rd-4th century tended to distance Adam’s sin with those of his posterity whereas the Latin Church Fathers, partially thanks to Augustine, linked the two. The Greek view culminated in Pelagianism and the Latin view in Augustinianism. Semi-Pelagianism linked Adam’s fall only with the pollution of sin but not its guilt. The Reformers sided with Augustine and the Socinians with Pelagius. Rationalists and evolutionists would discard with the concept of sin altogether. Berkhof notes that this was followed with a whole slew of unbiblical views:
“The idea of sin was replaced by that of evil, and this evil was explained in various ways. Kant regarded it as something belonging to the supersensible sphere, which he could not explain. For Leibnitz it was due to the necessary limitations of the universe. Schleiermacher found its origin in the sensuous nature of man, and Ritschl, in human ignorance, while the evolutionist ascribes it to the opposition of the lower propensities to a gradually developing moral consciousness. Barth speaks of the origin of sin as the mystery of predestination. Sin originated in the fall, but the fall was not a historical event; it belongs to superhistory (Urgeschichte). Adam was indeed the first sinner, but his disobedience cannot be regarded as the cause of the sin of the world. The sin of man is in some manner bound up with his creatureliness. The story of paradise simply conveys to man the cheering information that he need not necessarily be a sinner.”
From a biblical perspective, the Bible teaches that sin had a voluntary and ethical character, beginning with the transgression of Adam. The guilt of sin was imputed to all humans and its pollution was communicated to all humans (Rom. 5:12-21; Job 14:4). So Berkhof:
“Adam sinned not only as the father of the human race, but also as the representative head of all his descendants; and therefore the guilt of his sin is placed to their account, so that they are all liable to the punishment of death. It is primarily in that sense that Adam’s sin is the sin of all. That is what Paul teaches us in Rom. 5:12: “Through one man sin entered into the world, and death through sin; and so death passed unto all men, for that all sinned.” The last words can only mean that they all sinned in Adam, and sinned in such a way as to make them all liable to the punishment of death. It is not sin considered merely as pollution, but sin as guilt that carries punishment with it. God adjudges all men to be guilty sinners in Adam, just as He adjudges all believers to be righteous in Jesus Christ. That is what Paul means, when he says: “So then as through one trespass the judgment came unto all men to condemnation; even so through one act of righteousness the free gift came unto all men to justification of life. For as through the one man’s disobedience the many were made sinners, even so through the obedience of the one shall the many be made righteous,” Rom. 5:18,19.”
The effects of sin were disastrous for both the soul and the body. This resulted in what Calvinists refer to as total depravity. Humans become totally corrupted (Gen. 6:5; Ps. 14:3; Rom. 7:18) although this total depravity is only “total” insofar as no part of it is not affected by the fall. Humans became children of wrath according to our very nature (Eph. 2), thinking and acting according to the flesh rather than the Spirit (Rom. 8). From the perspective of the affects, it resulted in the presence of both shame and guilt. Humans became liable to both inevitable physical and spiritual death (Rom. 5:12; 6:23) apart from some sort of divine intervention.