Book excerpt: The Gospel Mystery of Sanctification presents the culmination of Puritan thought on living the Christian life. Combining doctrinal precision and pastoral sensitivity, Walter Marshall shows how sanctification is essential to spiritual life, dependent on spiritual union with Jesus Christ, and inseparable though distinct from justification. He shows how holiness involves both the mind and the soul of the believer and that it is the aim of the Christian life. It is no wonder that this book has been reprinted many times throughout the years and received such high praise from leading ministers of the gospel. "The most important book on sanctification ever written." John Murray (1898 1975), professor of systematic theology, Westminster Theological Seminary