The Lord Jesus is man’s peace because He reconciles men “to God in one body through the cross” (Ephesians 2:16). Sin alienates and leads to death. Transgression and disobedience sever sinners from their Creator as enemies. God in His great love and mercy provides the way by which believers may be reconciled and justified through the death of His Son (cf. Romans 5:10). The restoring of fellowship with the Father and the Son is also a bringing together of the saved into the relationship of the one body of Christ. Before the coming of Christ, Gentiles were “aliens from the commonwealth of Israel and strangers from the covenant of promise” (Ephesians 2:12). Now both Gentiles and Jews have the same access to God through the same message of peace in Christ. The two are made one in the body of Christ.
The body of Christ is the church (Ephesians 1:22, 23). The church was built and purchased by Christ. He is her Head and Savior. No other person is the Head of the church but the Son of God. Since Christ is not divided, there is one body of Christ (Ephesians 4:4). Many different religious bodies do not form His one body. When men do not submit fully to the authority of Christ the Head, they are not members of the one body of Christ.
Jesus prayed about unity. His petition was that believers may be one as the Father and the Son are one (John 17:20, 21). This oneness is achieved when men believe in Christ through the inspired word. Fellowship exists when believers abide in the doctrine of Christ (cf. John 8:31; II John 9). His teaching is “the word of reconciliation” (II Corinthians 5:19). By obeying the truth a believer is born again through the incorruptible word of God (I Peter 1:22, 23). Division is the result of men elevating man’s teachings and traditions above the gospel of Christ. The gospel is the message of peace that reconciles into the one true body of Christ.