groweth - “is growing” continually. Here an additional thought is added to the image; the Church has the growth of a living organism, not the mere increase of a building. Compare 1Pe 2:5; “lively stones ... built up a spiritual house.” Compare Eph 4:16; Zec 6:12, “The Branch shall build the temple of the Lord,” where similarly the growth of a branch, and the building of a temple, are joined.
holy - as being the “habitation of God” (Eph 2:22). So “in the Lord” (Christ) answers to “through the Spirit” (Eph 2:22; compare Eph 3:16, Eph 3:17). “Christ is the inclusive Head of all the building, the element in which it has its being and now its growth” [Alford].