The main reason biblical theology has no center is because the Scriptures are not given in a categorical manner, arranged like some systematic theology. Rather, the Bible is a simple narrative, presented in a linear, chronological manner. As such, there is no center to a timeline. All events assume a common beginning, build upon one another, and point toward the same climactic ending. Though there is no single idea that defines biblical theology, there are defining events which become characteristic within the apostolic witness.
Though the Day of Judgment will be radically apocalyptic, God is patient not wanting any to perish (2 Pet. 3:9). God is showing mercy in this age, waiting to make his enemies his footstool (Heb. 10:12f), for “God demonstrates his own love for us in this: While we were still sinners, Christ died for us.” (Rom. 5:8) This age is thus essentially cruciform, i.e. shaped like the Cross. And concerning the witness of redemptive history—especially the Cross and the Day of the Lord (cf. Acts 10:42ff)—God has given his Holy Spirit to confirm the truth (Acts 1:4-8). So the apostolic witness is also charismatic, depending wholly upon the gift of God to turn people from the wrath to come.
Many movements and traditions throughout church history have emphasized one or two of these elements (often to the detriment of other elements), but unfortunately few have sought a proclamation that holds them all together. We seek a holistic gospel witness that is creational, covenantal, cruciform, charismatic, and apocalyptic—“To the only wise God be glory forever through Jesus Christ!” (Rom. 16:27)