In Ephesians 3:17, Paul prays that Christ might “dwell in your hearts through faith,” being “rooted” and “founded” in love. Within the sentence structure, “in your hearts” is parallel to “in the inner person” in the previous verse. In Ephesians 3:16-17, then, both “to be strengthened with power through the Holy Spirit” and “for Christ to dwell in your hearts through faith” are individual realities. Christ dwells in the heart of each individual believer.
Previously, however, Paul had spoken about the entire church – both Jew and Gentile now as one in Christ through faith – being built together as a “holy temple in the Lord” and “a dwelling in which God lives by his Spirit,” established on the “foundation” of the apostles with Christ Jesus as the “cornerstone”. (Ephesians 2:19-22). Here, Christ dwells in the community of faith as a whole.
Paul, then, can use the same figure of speech to talk about both individual and corporate realities. The church is like a temple, but so is the individual Christian. Paul uses an architectural term – “foundation” – to speak about them both. (The noun themelios “foundation” in Ephesians 2:20; the passive form of the verb themelioo “to be founded” in Ephesians 3:17).
How are the corporate and individual realities related?
Most of the first three chapters of Ephesians deal with God’s eternal purpose of creating one new corporate people of God, now revealed and put into effect through the work of Christ. Ephesians 3:17 comes in the context of a prayer and doxology which Paul offers at the conclusion of this first section of his letter.
In his prayer, Paul asks that the corporate reality which God has created in Christ as part of his eternal plan (“the church is a holy temple and the dwelling place of God”) might become a living reality for every individual Christian (“for Christ to dwell in your hearts by faith”). It through faith in Christ, in fact, that every individual is incorporated into the corporate reality.