Book excerpt: English Puritans of the Stuart era were divided by a number of questions. The greatest of these asked what constitutes salvation and restoration from sin. All agreed that it was by grace through faith. But few could agree on how to define sin, grace, and faith. Richard Sibbes consciously followed Augustine, Martin Luther, and John Calvin in defining sin as self-love and grace as God's redemptive love in Christ. His theology centered on the love of God expressed through Christ and offered by the Spirit; and faith as a response to that love. This produced a winsome and transforming theology of union with Christ and communion with God. In this he was a counterweight to the spread of moralistic Puritan theologies in his day.