The vocabulary of Ephesians is is rich in “house” and “building” words. Most of them show up in a good English translation, but there are several more in the original Greek. At some points, Paul seems almost to be punning on “house” words, or Greek words made from the oik- root.
For example, a key passage in 2:19 says “so then you are no longer strangers and aliens [par-oik-ioi], but you are fellow citizens with the saints and members of the household [oik-eioi] of God.” Not par-oikioi, but oikeioi: That is, you are no longer outside of the home of God, but you are, well, homies. The passage goes on: you homies are
built [ep-oik-odomethentes] on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone, in whom the whole structure [oik-odome], being joined together, grows into a holy temple in the Lord. In him you also are being built together [sun-oik-odomeisthe] into a dwelling place [kat-oik-eterion] for God by the Spirit.
A couple of times Paul talks about building each other up, and uses oik-words to do so:
4:16 the body builds itself up [oik-odomen] in love;
4:29 only such talk as is good for building up [oik-odomen]
–which is interesting because in English we also “edify” each other, as if we were “edifices.”
More significantly, Paul refers in Ephesians to his own ministry as a stewardship, which is a great word with oik hidden in it: 3:1, “the stewardship [oik-onomian] of God’s grace that was given to me for you.”
And most important of all, Paul twice uses one of these “house” words to refer to God’s all-encompassing plan that is now being decisively carried out in the spread of the gospel. In 1:10 he says that God has made known to us “the mystery of his will, according to his purpose, which he set forth in Christ as a plan [oik-onomia] for the fullness of time, to unite all things in him, things in heaven and things on earth.” And similarly, in 3:9 Paul says that in his own preaching of the unsearchable riches of Christ, he is bringing to light “what is the plan [oik-onomia] of the mystery hidden for ages in God who created all things.”
The translation “plan” doesn’t really help us understand what’s housey or homey or oiky about this divine oikonomia. But by using the word, Paul is alluding to the principle of household management, the law of the house, the nomos of the oikos. God is the Father from whom all families in heaven and earth get their name, and salvation history is his house. He orders that house wisely. Some of the best parts of Ephesians are sections where Paul praises the manifest wisdom of God as it is being displayed in this economy, or dispensation, or wise household management, of God. In Ephesians, Paul is especially focused on the unity of Jews and Gentiles. God’s economy has broken down the wall dividing them; the revealed mystery is that in the fullness of time the two have been made one new man. All of that, with its deep theological presuppositions and its eschatological implications, is what God is up to as Father and head over this wisely administered household.