I’ve never met Joshua Jipp, but I think of him as a friend. He understands how central the kingdom of God is to the New Testament, and he explains it in The Messianic Theology of the New Testament (Grand Rapids, MI: Eerdmans, 2020).
Here’s a little of what he says about Ephesians. We miss the message if we treat “Christ” merely as a name for Jesus rather than as God’s anointed ruler bearing his authority:
[p.218] The Messiah’s resurrection and enthronement by God is understood through the lens of Psalms 8 and 110 (Eph 1:20–23), the Messiah’s defeat of his hostile enemies through Psalm 2 and Daniel 7 (Eph 1:21; 2:1–3), the Messiah’s establishment of peace for his people through Isaiah (Isa 9:5–6; 52:7; 59:17; Eph 2:14–18), and the Messiah’s giving of gifts to his people with the help of Psalm 68 (Eph 4:7–11). Paul’s deployment of these royal texts from Israel’s Scriptures to refer to “the Christ” in Ephesians suggests Paul uses Χριστός [Christos]] to mean “Messiah.”
So, if Christ is God’s anointed ruler (Messiah), who are we? We’re the people he governs, the community in his care, the people who live in Christ:
[p.223] Those who are “in Messiah Jesus” (ἐν Χριστῷ Ἰησοῦ, Eph 2:6b, 7b) participate in the Messiah’s resurrection and enthronement. Thus, God has “made them alive together with the Messiah” (συνεζωοποίησεν τῷ Χριστῷ, 2:5), “raised them together” (συνήγειρεν), and “seated them together in the heavenly places in Messiah Jesus” (συνεκάθισεν ἐν τοῖς ἐπουρανίοις ἐν Χριστῷ Ἰησοῦ, 2:6). The three σύν- prefixed compound verbs in Ephesians 2:5–6 recall Paul’s use of Psalm 110 in Ephesians 1:20–23, but here he applies the royal notion of resurrection and enthronement to all who are in Messiah Jesus, thereby royalizing the king’s subjects.
In Christ, we share his presence in the way a body shares in the life of the head. This imagery was already in use in Roman propaganda:
[pp. 228-229] Seneca repeatedly refers to Nero as the “head” and “mind” over the body of the empire and as the one who stabilizes the empire and unites his people: “the whole body (corpus) is the servant of the mind” and “the vast multitude of men surrounds one man as though he were its mind, ruled by his spirit, guided by his reason” (1.3.5); the emperor is “the bond by which the commonwealth is united, the breath of life which these many thousands draw,” for the empire would be prey were the “mind of the empire to be withdrawn” (1.4.1). For Seneca, the function of the head (emperor)/body (empire) metaphor is to stress the remarkable connection between the ruler and the ruled such that Nero will care for and not harm his own body.
… Paul’s employment of the metaphor in Ephesians 1:22–23 portrays the Messiah as the cosmic ruler of the universe. But the church as the Messiah’s body does not sit passively under the rule of its head; rather, Paul claims that the church shares in the Messiah’s rule by extending his dominion in all places. Such a claim is both the essence and function of the church — to fill the created world with the presence of its king. This is the force of Paul’s claim that the church is “the fullness of the one filling all things in all places.”
Christ is the only ruler who can establish peace, unifying the diverse peoples of the earth as one new humanity in himself:
[p.230] In his Precepts of Statecraft, Plutarch says that “peace, liberty, plenty, abundance of men, and concord are the greatest blessings that cities can enjoy,” and therefore a primary responsibility of the ruler is to “instill concord and friendship in those who dwell together with him and to remove strifes, discords, and all enmity” (Moralia 824D). Thus, the language of (making) peace, reconciliation, and communal harmony are frequently spoken of as a necessity for successful kings and rulers. The successful king usually brought about this peace and harmony through the violent pacification of the king’s enemies. J. Rufus Fears refers to this aspect of royal ideology as “the theology of victory.”
So how does Christ do what no other leader has been able to do, ending the enmity, humanizing our humanity?
[pp.231-232] It is no surprise that Paul portrays the Messiah as an ideal king who eradicates the ethnic hostility between Jew and gentile and transforms the two groups into one peaceful body. What is remarkable, however, is that the messianic king conquers and kills the “hostility” between Jew and gentile, not through the usual weapons of political warfare, but by means of his bloody death on the cross: “but now in Messiah Jesus, you who were far off have been brought near by the Messiah’s blood” (2:13). Paul speaks of the Messiah as a conquering king who defeats and destroys the social enmity: he “destroys … the enmity in his flesh” (2:14); “he tears down (καταργήσας) the law with its decrees and commands” (2:15a); “he reconciles (ἀποκαταλλάξῃ) both groups into one body for God through the cross” (2:16a); and “he kills the enmity by [the cross]” (ἀποκτείνας τὴν ἔχθραν ἐν αὐτῷ, 2:16). Paul’s language of the Messiah as “destroying,” “tearing down,” “reconciling,” and “killing” conforms well with depictions of conquering kings who pacify and reconcile through violence, as we have seen, and yet Paul transforms this trope by declaring that the Messiah has created a new people by absorbing their enmity and hostility in his flesh, that is, through his bloody death on a cross.
This defines who we are and what we are called to be, the reason the church exists as his functioning body in the world he rules:
[p.233] The Messiah’s resurrection and exaltation over his enemies enables him to give gifts to his people that produce peace, harmony, and growth within the community (4:11–16).
These brief quotes are from part of Chapter 7 where Jipp discusses Ephesians. He shows how the whole New Testament is centred on Christ — God’s anointed ruler for the restoration of the earth into his governance. The Christ is the good news.