Based on Romans 7:21 ‘I find then a law, that, when I would do good, evil is present with me’, Owen’s work shows that sin is a powerful inward law or principle lodged in the heart whose whole nature is enmity against God. This powerful river, flowing from the Fall, can only be brought under control by regenerating grace. However, sin’s enmity remains in believers after conversion, and the long war against it is one in which all Christians must engage. Though this is a book about sin, it is no less about the all-sufficient grace of Christ. There is much here to strengthen and comfort the believer. Abridged and made easy to read, this is intended as a companion volume to ‘The Mortification of Sin’ and ‘Temptation Resisted and Repulsed’, both in the Puritan Paperback series.