Heilsgeschichte is a good German word that is often translated as “salvation history” or “the history of redemption,” and in his essay entitled “The Covenant Relationship,” Scott Hafemann explains the meaning of “the history of redemption.” According to Hafemann, God’s self revelation occurs through actual events in history. Thus, God’s involvement in the world and with his people as conveyed in the Scriptures are not merely subjective human religious experiences. Rather, the Scriptures are God’s revelation of his real historical acts of rescuing humanity from evil, rebellion, sin and death. This is the history of redemption. This is the one, true, unified redemptive story from creation to new creation.
The biblical history of redemption is theocentric, and so the discipline of Biblical Theology is properly focused on God’s self-revelation of his character and his relationship with his people within salvation history. Moreover, within Biblical Theology, the theme of covenant is essential to understanding salvation history and the God‒human relationship because throughout the biblical narrative, “this relationship is expressed in and defined by the interrelated covenants that exist throughout the history of redemption.” Although it is important to note that the interrelated covenants all pointed to the one relational covenant between God and his people. This covenant relationship is summarized in the ‘covenant formula’ where God declares, “I will be your God and you shall be my people,” and this covenant relationship provides the interpretive lens and the structure for understanding who God is and how he relates to his people within the unity and diversity of the biblical narrative.
With this idea of covenant as an integrating concept of Scripture, Hafemann offers three important distinctions to consider. First, the distinction between covenant terminology and covenant reality. Interpreters should not despair at the scarcity of covenant terminology and its uneven use because the reality of covenant is present through other descriptive elements and imagery.
Second, the distinction between the establishing of the formal covenants and the continuing personal relationship they initiate, presuppose, ratify and embody. This distinction recognizes the formal and legal aspects of covenants within the relationship to which they exist, but covenants are not equivalent to the relationship. In other words, the relationship can occur apart from the creation of a specific or formal covenant, but a covenant can then extend to the existing relationship.
Third, the distinction between the covenant relationship throughout history and the covenant epochs within history. This involves the recognition that the Bible divides history into two epochs: this age and the age to come, and throughout this two-age concept, the Bible divides God’s relational history into the old covenant and new covenant.
In view of these distinctions, Hafemann advocates for “unity reading of the Bible.” He explains that the Bible is “built upon a two age, two covenant conception, within which the individual covenants play their respective roles in the unfolding drama of a continuous history of salvation.” Thus, the Bible should be read as one, unified story about God and his covenant people within two epochs and with individual covenants throughout redemptive history.
 Scott J. Hafemann, “The Covenant Relationship” in Central Themes in Biblical Theology: Mapping Unity in Diversity, edited by Scott J. Hafemann and Paul R. House (Grand Rapids, MI: Baker Academic, 2007), 20-21.  Hafemann, “The Covenant,” 21.  Hafemann, “The Covenant,” 21-23.  Hafemann, “The Covenant,” 24-25.  Hafemann, “The Covenant,” 25-26.  Hafemann, “The Covenant,” 27-28.  Hafemann, “The Covenant,” 29.  Hafemann, “The Covenant,” 29-30.