Summa doctrinae de foedere et testamento Dei

Johannes Cocceius's Summa doctrinae de foedere et testamento Dei (1648) is a significant work in Reformed theology that centers on covenant theology. Cocceius proposed that the relationship between God and humanity is defined by covenants. He outlined an original "covenant of works," where salvation was contingent on perfect obedience. After humanity's fall into sin, this was superseded by the "covenant of grace," where salvation is a divine gift.1

This covenant of grace, originating from an agreement within the Trinity, unfolds through historical stages, ultimately leading to the Kingdom of God. Cocceius used the covenant of works to address social and political matters and interpreted Old Testament symbols as prefigurations of Christ within the covenant of grace, thereby strengthening biblical piety and introducing a concept of salvation history into Reformed theology.1