The church at Ephesus was established in Acts 19, when the apostle Paul encountered a group of about a dozen men (evidently Gentiles) who were disciples of John the baptizer (vv. 1-7). When he realized that their understanding was incomplete, Paul told them “the rest of the (gospel) story” and they were baptized into Christ.
The letter to the Ephesians is one of the “prison epistles” (Ephesians, Philippians, Colossians, and Philemon), written during the time when Paul was imprisoned in Rome (around 60 A.D.). Unlike the Corinthian or Roman letters, Paul did not write (to the Ephesians) to correct error, so much as to explain in detail the fundamental principles of the gospel and the impact of God’s grace in our lives. His first point (in 1:4), is that every spiritual blessing originates with God, and that these blessings are only available “in Christ.” It is important for us to understand the implication of this statement, because we can easily mistake God’s “general” goodness (Matthew 5:45) for His spiritual blessings. The fact that He is kind and generous to all people (even those who hate Him) should not be interpreted as proof that He approves our behavior. We can know with certainty that He approves what we’re doing only when we follow His instructions (1 John 3:22).
Paul explains the relationship of grace and faith in Ephesians 2:1-10. Sin separates us from God (the Source of life) according to Isaiah 59:2 and 1 John 3:4, which is the definition of spiritual death. Paul notes (vv. 1-3) that this was the condition of the Ephesians before they became Christians. Here, Paul is showing us that God’s grace (His offer of salvation) combined with human faith (our reception/ acceptance of God’s offer) is what results in our salvation. This could also be expressed as “God’s participation combined with man’s cooperation yields victory over sin!” It is important that we read accurately the words of Ephesians 2:5 and 8, because if “grace” in verse 5 means grace “only” (as some Protestant theologians claim), then this rules out even the faith mentioned in verse 8. It is also important point out that “faith” in verse 8 is not the same as “faith only.” (James explains in James 2:17-24 faith only is actually “dead” faith). The only way faith can live and be effective in obtaining the blessing of God’s grace is for it to be expressed in obedient action – just as the word directs.
Notice also that Ephesians 2:11-22 says that there are no Jews or Gentiles “in” Christ; all who obey the gospel are united together as one body, one people in Him. In this way we are able to return to the condition that existed in Abraham’s day, when all people were equal and there were no Jews or Gentiles. At verse 18, Paul also shows the active involvement of all three Persons of the Godhead (Father, Son, and Holy Spirit) in our salvation from sin.