Tychicus, one of Paul’s coworkers, carried the letter to the Ephesians from Rome to the congregation in Ephesus. (Eph 6:21, 22) Paul also had Tychicus deliver a letter to the Christians in Colossae.​—Col 4:7-9.

 There are a number of similarities between this letter and the one to the Colossians. Paul wrote both letters about the same time, during his first imprisonment in Rome. No doubt, the congregations had similar needs. As an example, compare Eph 5:19 and Col 3:16.​—See “Introduction to Colossians.”

 Unity is the theme of this letter. Paul shows that it is Jehovah’s purpose to restore unity among all His intelligent creatures, and he tells of the roles that Christ’s sacrifice and the “gifts in men” play to that end. (Eph 1:9-11; 2:11-16; 4:1-6, 8, 11-13) Following Christ’s example and being “in subjection to one another” contribute to unity in Christian families.​—Eph 5:21–6:4.

 The counsel that Paul gives in his letter is fitting in view of the circumstances under which the Ephesian Christians were living. For example, consider the following background information.

•  In the first century C.E., the city of Ephesus was noted for its great wealth. It was a major port city and the end point of a road system for transporting goods from the East. An author of ancient times wrote that the city had become “the general treasury of Asia.” People from many places deposited their possessions in its temples. However, Paul wrote to the Christians in Ephesus about true riches, spiritual ones.​—Eph 1:7, 18; 2:7; 3:8, 16.

•  Ephesus was well-known for its gross sexual immorality. Paul warns against sexual immorality, saying that it should not even be mentioned among Christians. (Eph 5:3-5) Christians need to put on “the new personality.”​—Eph 4:20-24.

•  The city was noted for the worship of the fertility goddess Artemis at the pagan temple, which was considered to be a wonder of the ancient world. (Ac 19:19, 27) By contrast, Paul points out that anointed Christians are part of “a holy temple,” in which Jehovah dwells by his spirit.​—Eph 2:21.

•  Ephesus was a center for demonism. (Ac 19:11-20) Paul encourages the Christians to fight against wicked spirits by putting on “the complete suit of armor from God.”​—Eph 6:11, 12.

 Early writers confirm that Paul wrote the letter and that it was “To the Ephesians.” Among such writers are Irenaeus (second century C.E.), Clement of Alexandria (second century C.E.), and Origen (third century C.E.).