Complex sentence: Concepts foundational to covenant theology can be found in the writings of Church Fathers such as Irenaeus and Augustine, but the reformer John Calvin ("Institutes" 2:9-11) was the first to organize God's salvation economy under the categories of covenant theology.
Split into simpler sentences: Concepts foundational to covenant theology can be found in the writings of Church Fathers such as Irenaeus and Augustine. The reformer John Calvin ("Institutes" 2:9-11) was among the first to organize God's salvation economy under the categories that would become covenant theology.