The subject of this book is the understanding of the gospel in the theology of the Protestant Reformer John Calvin. Specifically, it deals with what Calvin terms the 'twofold grace of God', the justification and sanctification of believers on the basis of the redemptive work of Christ. In treating this subject, the study has a twofold objective: first, to contribute to an understanding of the nature and relation of justification and sanctification in Calvin’s theology; and second, to contribute to the interpretation of Calvin’s theology in general. The thesis of the book is that Calvin views justification and sanctification as the two benefits of the Triune God’s work of redemption in Jesus Christ. These benefits are simultaneously communicated to believers through the office or ministry of the Holy Spirit, who joins them to Christ by faith. The 'twofold grace of God' represents a particular doctrinal theme within the broader framework of the knowledge of God as Creator and Redeemer. Redemption, which remedies the consequences of human sinfulness, includes not only the restoration of sinners to a state of acceptance and favour with God on the basis of Christ’s work as Redeemer (justification), but also the renewal or sanctification of sinners in conformity to Christ (sanctification). The 'twofold grace of God' reveals distinct features of the knowledge of the Triune God as Redeemer, who is merciful and kind in condescending to his creatures’ needy condition and raising them up to newness of life. The 'twofold grace of God' in Calvin’s theology provides a comprehensive perspective upon the knowledge of God and ourselves that peculiarly concerns the redemption of sinful humanity. This study also addresses several controversial questions in Calvin studies. These include Calvin’s view of the relation between the law and gospel, and his understanding of the role of good works in confirming the genuineness of faith.