Biblical theology and systematic theology are two different manners of arranging the teaching of the scriptures. Biblical theology seeks to understand the progressive unfolding of God’s special revelation throughout history, whereas systematic theology seeks to present the entire scriptural teaching on certain specific truths, or doctrines, one at a time. Biblical theology is thus historical and chronological in its design; and in fact, a close synonym for biblical theology, at least in its wide-angle task of accounting for all of special revelation, is the term “redemptive history”. Biblical theology is not always pursued in so broad a fashion, however; sometimes, certain themes are approached in a biblical theological manner; for instance, a biblical theology of holy space in worship would seek to understand how that specific motif unfolded in redemptive history, from the beginning of revelation until the end. Another narrower application of biblical theology would be the study of the unfolding of revelation during a specific time period (for example, post-exilic biblical theology); or the study of the development of themes in a particular author (for example, Johannine biblical theology); but ultimately, even these narrower applications are truly biblical-theological in nature only as they seek to advance an understanding of the progression of redemptive history as a whole.
Systematic theology, on the other hand, is laid out, not chronologically, nor with a consideration of the progressive development of doctrines, but thematically, taking into account from the outset the complete form which revelation as a whole has finally assumed. Systematic theology attempts to answer the question, “what is the full extent of the truth that we may know about the doctrine of sin, or salvation, or the Holy Spirit, etc.?”. Hence, systematic theologies progress from the doctrine of the Godhead, or theology proper, to christology, pneumatology, angelology, soteriology, and so on, treating each theme exhaustively.