Both Ephesians and Colossians begin with Paul addressing the recipients as “faithful” and “saints” who are “in Christ” (Ephesians 1:1, Colossians 1:2). He goes on to tell the Ephesians that they are blessed in Christ (1:3), chosen in Christ (1:4), and redeemed in Christ (1:7). He lets them know that they have an inheritance in Christ (1:11), that they trusted in Christ (1:12-13), and that they sit together with Christ in the heavenly realms in Christ (2:6) — and all that in the first chapter and beginning of the second chapter!
Throughout the rest of the book, Paul declares how the Ephesians have been brought near to God by the blood of Christ (2:13) and are partakers of His promise in Christ (3:6). Their boldness and access to God comes because they have faith in Christ (3:12).
Significantly, it is emphasized by Paul that God accomplished His eternal purpose “in Christ” (3:11). All of the other occurrences of this phrase have as their focus and recipient the believer. This use (3:11) is focused upon God’s work. God accomplished His work “in Christ.”
The faith of the Christians in Colosse is described as being “in Christ” (Colossians 1:2). All things consist “in Christ.” Jesus is the one who holds all things together. All of deity dwelt “in Christ” (1:19, 2:9). The goal of ministry is to present every man perfect in Christ (1:28). Christians are to walk in Christ, be built up and established in Christ (2:6-7). Faith makes one complete in Him (2:10), being spiritually circumcised in Him (2:11)
The phrase “in Christ” describes the Christian’s new reality of living entered into by faith. It is a comprehensive term which encapsulates all the aspects of our divine relationship with God through Jesus Christ. In short, we are seen by God the Father in the same light as He sees His Son Jesus Christ. The work of Jesus Christ dying on the cross to secure salvation for all who believe was the eternal plan of God the Father. All is centred on Jesus Christ. All who believe are “in Him” and, as John wrote, He is in us and is the source of all that is good (John 15:4-5).