God relates to humankind through Covenant.
Beginning in Adam and culminating in Christ, there is an historical continuity of God’s covenant relationship with mankind, expressed through various administrations (e.g. Adamic, Noahic, Abrahamic, Mosaic, Davidic, Messianic). As the outshining of God’s nature and character, God’s law is the ground of covenant. Based on obedience to that law, the covenant is designed for human flourishing.
Significantly, there is a five-fold covenant structure that provides the ground of God’s dealings with man, from the individual, through families, the redeemed community, to nations. This five-fold structure is not only evident in various books of the Bible (e.g. Deuteronomy, Revelation) but also throughout ancient near-eastern cultures. It can be conveniently remembered through the acronym THEOS: Transcendence, Hierarchy, Ethics, Oath, Succession. All the covenants of antiquity between a victorious king and his vassals were according to this pattern. It establishes the authority of the king (transcendence, hierarchy), outlining the conditions of it (ethics), the penal consequences of rebellion (oath), and its future continuity (succession). While all God’s dealings with man are imbued with his paternal heart, he has enthroned his Son as the victorious King and we are his vassals. We are now under his government and law. And just as every civil government of man has a legal constitution, likewise, God’s government (i.e. the kingdom of God); its constitution is the covenant with its stipulations (conditions–ethics/law) and sanctions (consequences–oath/penalties). Covenant fidelity, therefore, either invites the blessing of God and human flourishing. Or conversely, covenant infidelity invites historical judgements and human suffering—God’s remedial disciplines.
Christ, as the God-man, succeeds in what Adam failed to do: to perfectly obey the covenant through filial love, and thus, merit the favour of God and inherit the Kingdom. Furthermore, on our belhalf, he pays the judical penalty for broken covenant: death. By faith Christ’s merit is credited to our account. On our behalf he has fulfilled the covenant conditions (obedient life) and paid the covenant consequences (obedient death). Now restored to covenant obedience, as his fellow-heirs, we thus also inherit the Kingdom of God, regaining what Adam had lost—not only intimacy with God but also dominion as his vice-regents in the earth.
Covenant is thus the core motif of the Bible and the rationale for the Gospel and its cultural mandate. Without understanding it and how it functions we are biblically illiterate.
God’s nature nor purpose have changed; covenant continuity flows into the 21st century with full ethical force for all individuals and nations.
Consequently, Covenant and Kingdom are motifs joined at the hip—the kingdom of God comes to the earth through covenant obedience.