Sin is not simply moral evil as recognised by the awakened human conscience, but guilt before God or the gods. Some doctrine of sin, and of the mode of averting the anger of the deity, of reconciling him, and of escaping from the guilt, is accordingly part of most religions, ancient and modern. Zoroastrianism is a conflict of sin and holiness. The central doctrine of Buddhism turns on the demerit of human actions and human life, which must be purged by transmigration. But in no sacred books is the sense of sin so keen and developed as in the Bible—in the writings of the prophets of the God of holiness, in the psalms, in the gospels, and in Paul's epistles. From Paul's various utterances on the great subject of sin the latest Christian doctrine professes to be but a development.
Throughout the Scriptures sin appears as that element in man which puts him at enmity with God, and for his salvation from its guilt and power required the work of a Redeemer (see CHRISTIANITY). Sin is not defined in Scripture, and it was not till the controversies between Pelagius and Augustine, at the end of the 4th century, that the doctrine received full development. The early Greek fathers regarded sin as opposition to the will of God, and as such involving death as its just penalty. But they did not affirm that the guilt of Adam's sin or the corruption of his nature descended to all mankind. Tertullian, in virtue of his doctrine of Traducianism, was bound to hold that sinfulness had been propagated from Adam to his descendants. But it was reserved for Augustine to maintain, against Pelagius, that Adam's sin completely corrupted his whole nature; that the corruption of his guilt and its penalty death pass to all his children; that man is born not merely corrupt, but in a state of sin, guilt, and liability to punishment; in virtue of Adam's peccatum originale, the offspring of Adam is a massa perditionis, incapable of knowing, or loving, or serving God, and naturally disposed, without grace, to pursue evil only, the will being enslaved to evil. Pelagius (q.v.) maintained contrary doctrines, and semi-pelagianism insists that in spite of the weakening of his powers through hereditary sinfulness man is yet not wholly inclined to evil. The Greek Church continued to deny hereditary guilt, and to affirm man's will as free as Adam's before the fall. Duns Scotus and his followers admitted that man had lost by Adam's fall iustitia originalis, but laid stress on the freedom of the will. Thomas Aquinas taught that hereditary sin is truly sin, and the unbaptised infant is damned. At the Reformation both Luther and Calvin asserted what they regarded as Augustinian and Pauline views. Zwingli looked on hereditary sin as an inherited evil or disease: Arminians and Socinians practically denied hereditary sin altogether. In modern German speculation the Hegelians taught that sin was a necessary condition of the development of mankind; and Schleiermacher that the sinful state of man was a disturbance of his nature, not a necessary condition of it. The problems connected with sin are closely akin to those connected with the origin of evil and the freedom of the will.
The doctrine of the Thirty-nine Articles (Art. ix.) is as follows: 'Original sin standeth not in the following of Adam (as the Pelagians do vainly talk); but it is the fault and corruption of the nature of every man, that naturally is engendered of the offspring of Adam, whereby man is very far gone from original righteousness, and is of his own nature inclined to evil, so that the flesh lusteth always contrary to the spirit; and therefore in every person born into the world it deserveth God's wrath and damnation.'
The Westminster Confession teaches (chap. vi.): 'By this sin' (i.e. the eating of the forbidden fruit) 'they' (i.e. our first parents) 'fell from their original righteousness and communion with God, and so became dead in sin, and wholly defiled in all the faculties and parts of soul and body. They being the root of all mankind, the guilt of this sin was imputed, and the same death in sin and corrupted nature conveyed to all their posterity, descending from them by ordinary generation. From this original corruption, whereby we are utterly indisposed, disabled, and made opposite to all good, and wholly inclined to all evil, do proceed all actual transgressions.'
Sins have been divided into categories, as sins of omission and of commission, deliberate voluntary sins and involuntary sins, sins of infirmity, &c. The 'sin unto death' (1 John, v. 17), generally identified with the unforgivable 'blasphemy against the Holy Spirit' (Matt. xii. 31), or 'sin against the Holy Ghost,' is understood not to mean profane speaking against the person of the Holy Spirit, or resisting His operations, but a state of obstinate, malignant deadness of heart, and unrepentant and unhesitating hatred to all good. The distinction accepted by Catholic theology between mortal and venial sins is explained at CONFESSION.
See ADAM, ATONEMENT, AUGUSTINE, CHRISTIANITY, DEVIL, ETHICS, EVIL, FALL, HELL, PAUL, PELAGIUS, SACRIFICE, TRANSMIGRATION, WILL; also Julius Müller's Christliche Lehre von der Sünde (1839-44; Eng. trans. from 3d ed. 1852, 5th ed. 1877); Principal Tulloch's Christian Doctrine of Sin (1876), and A. Brown's Doctrine of Sin (1881); Cardinal Manning's Sin and its Consequences (1874); Ernest Naville's Problem of Evil (Eng. trans. 1872); Rev. O. Shipley's Theory about Sin (1874), and Principles of the Faith in Relation to Sin (1878).