4:4 one body. The doctrine of Christian unity, including both doctrinal and spiritual unity, incorporates seven units: one body, composed of all the individual members that make up a body, as stressed by Paul (I Corinthians 12:12); one Spirit who indwells each believer and has baptized them into that body (I Corinthians 12:13); one hope, centered on Christ’s return to complete His work of redemption (Ephesians 1:14; Titus 2:13); one Lord, Jesus Christ, who has purchased each believer with His own blood (Ephesians 1:7; I Peter 1:18-19); one faith, that body of truth which has been “once [for all] delivered unto the saints” (Jude 3); one baptism, by which we have all been identified with and united with Christ; and one God and Father of us all.

4:5 one faith. All people, even atheists, have faith in something. The Christian faith, however, is the only saving faith (Ephesians 2:8). It is an understanding faith (Hebrews 11:3), a justifying faith (Romans 5:1), a purifying faith (Acts 15:9), a living faith (Galatians 3:11), a stable faith (II Corinthians 1:24), and a triumphant faith (I John 5:4). But this true faith may be rare on earth when Christ returns (see note on Luke 18:8).

4:5 one baptism. Whether this “one baptism” refers to Spirit baptism or water baptism has been extensively argued. Since both aspects of baptism are taught in the Bible, with water baptism being the visible sign and testimony to the Spirit’s baptism, and since no modifying words or phrases are attached to the word here to identify it as one or the other, it is probable that both aspects are in view, it being implicit that both go together in one unifying reality. See notes on I Corinthians 12:13 and Romans 6:3-5.

4:6 One God and Father. Note another reference to the three Persons of the Godhead in these verses (compare Ephesians 1:17; 2:18; 3:14-19)—the Spirit (Ephesians 4:4), the Lord (Ephesians 4:5), the Father (Ephesians 4:6). The Father is above all things; the Son manifests God through all things; and the Spirit is in all believing Christians.