Having previously labored among them for three years, Paul wrote a letter to the Church in Ephesus.  Though we might expect the letter will be informal, a chance for friends to catch up, these introductory verses make it clear that Paul is writing with a purpose; he is speaking as an Apostle on behalf of Christ.  Even though he had already instructed them and they were a healthy, thriving church, this letter opens like Paul's other letters - not with tips for living and a focus on commands but with a heavenly greeting, announcing that God is gracious and peaceable toward them in Christ.  Though they were a healthy church, the Ephesians still needed to hear Christ's message of grace.