Brevard Childs:

The church’s continual struggle in understanding the literal sense of the text as providing the biblical grounds for its testimony arises in large measure from its canonical consciousness. On the one hand, it recognizes that textual meaning is controlled by the grammatical, syntactical, and literary function of the language. On the other hand, these formal criteria are continually complemented by the actual content of the biblical texts which are being interpreted by communities of faith and practice. The productive epochs in the church’s use of the Bible have occurred when these two dimensions of scripture constructively enrich and balance each other as establishing an acknowledged literal sense.

— Biblical Theology of the Old and New Testaments, 724

Five points, both historical and theological, to render credible the preaching of New Testament slavery texts:

1. Slavery in the Greco-Roman world is not to be equated, historically speaking, with antebellum American race-based chattel slavery.
2. Nevertheless, Greco-Roman slavery was, from the perspective of Christian morality, a violent, unjust, and dehumanizing system: differently shaped in the form of its evil than the American form, but reprehensible nonetheless.
3. The New Testament canon contains both (a) prudential, theologically grounded guidance for life under such a system and (b) moral and theological lessons that, developed and applied over time within a Christianizing society, should have — and largely did — inevitably resulted in the eradication of the slave system.
4. These different witnesses are not to be conflated, even when they emerge from the same texts (e.g., the book of Philemon), but neither are they in opposition to one another. The Christian tradition, drawing on this textual heritage, is right to now condemn all forms of slavery as unjust violations of divine law. Neither does this obviate the moral responsibility of those who exist within systems of slavery to adhere to Christian ways of living.
5. The fact that the New Testament and early Christian “strategy” (a misleading word in this context) for the eradication of slavery involves, in a sense, accommodating its ongoing existence during the Christianization of society is not a warrant against, in a modern society with its moral norms already re-framed by Christianization, using appropriate mechanisms of law and even force to destroy enduring systems of enslavement. To say that would be to simultaneously radically enlarge and disastrously narrow the sufficiency of Scripture.

Brevard Childs:

The early church’s theological reflection on the God of Israel did not turn on certain isolated Old Testament passages from which to find a warrant for a developing christology, but rather it turned on the issue of the nature of God’s presence within the life of Israel in all its historical specificity. The God of the covenant who had bound himself to a people in love, had revealed himself as both transcendent and immanent, seen and unseen, the God of the Patriarchs and of all nations. The church confessed to know a totally sovereign creator who yet chose to reveal himself in the forms of his creation, who entered time and space in order to redeem the world. In short, the church’s reflection on God found itself inexorably drawn into Trinitarian terminology in order to testify to God both as the revealed and revealer, the subject and object of self-manifestation.

— Biblical Theology of the Old and New Testaments: Theological Reflection on the Christian Bible, 369.

Brevard Childs:

[The] history of interpretation serves as a major check against all forms of biblicism in showing the distance between the biblical text and the interpreter and the degree to which the changing situation of the reader affects one’s hearing of the text. This observation should not lead to cultural relativism, but to a profounder grasp of the dynamic function of the Bible as the vehicle of an ever fresh word of God to each new generation. It is a strange irony that those examples of biblical interpretation in the past which have truly immersed themselves in a specific concrete historical context, such as Luther in Saxony, retain the greatest value as models for the future actualization of the biblical text in a completely different world. Conversely those biblical commentators who laid claim to an objective, scientific explanation of what the text really meant, often appear as uninteresting museum pieces to the next generation.”

— Biblical Theology of the Old and New Testaments: Theological Reflection on the Christian Bible, 88