sin, in religion, unethical act. The term implies disobedience to a personal God, as in Judaism, Christianity, and Islam, and is not used so often in systems such as Buddhism where there is no personal divinity. In ancient Israel, besides personal sin there was national sin, usually idolatry; to regain God's favor the whole people had to be purified. Ex. 32–34. Crimes of a few might also be visited on all, but punishment of the criminals could avert this. Joshua 7. Apart from original sin, Christianity and Islam have no developed idea of collective sin. As to what constitutes sin, Christian ideas differ. Some Christians divide human acts into good, indifferent, and bad; others regard all acts not positively good as necessarily sinful. Thus, some may think gambling is indifferent so long as no obligation is infringed, while others consider gambling wrong as such. The traditional view, presupposed by Christian asceticism, is that a major way to perfection lies in performing or in refraining from indifferent acts solely to please God. The theory that no act is really indifferent is common among conservative "evangelical" Protestants. For Christians, the effect of sin may be twofold, since a sin is at once a rebellion against the omnipotent Creator, risking punishment (even hell), as well as a cause of the interruption of grace, a notion that was popularized in the Middle Ages, notably by the Cistercians in the 12th cent. and the Franciscans in the 13th. It is explicit in Western mysticism and in modern Roman Catholic teaching. Among Protestants it was typical of Martin Luther and John Wesley. In Western theology (particularly Roman Catholicism) sins are mortal if committed with knowing and deliberate intent in a serious matter; other sins are venial. Habitual sin is called vice. Roman Catholics are required to confess individually all mortal sins (see penance). The seven deadly, or capital, sins are pride, covetousness, lust, anger, gluttony, envy, and sloth. The sins that cry out to heaven for vengeance are willful murder (Gen. 4.10), the sin of Sodom (Gen. 18.20,21), oppression of the poor (Ex. 2.23), and defrauding the laborer of his wages (James 5.4). The sin of the angels (specifically of Satan) is pride. The opposite of sin is virtue, but in Christian practice the opposite of sin is grace, i.e., the merits of Christ's virtues given to humanity. See atonement; baptism; ethics; purgatory.