What is Ephesians all about?

Yesterday, I gave an overview of Ephesians based on five key phrases from the book.  We can however get a little bit tighter as we seek to sum up what the main message of the book is.  Whenever I prepare a sermon, I try to sum up the core message in one or two sentences.  It is possible to do this for a single sermon based on a chapter or passage.  We can also do this with a whole book of the Bible and so for a whole series. So what is Ephesians all about?  Well, I would suggest the following.

Ephesians is about how God has united us together with himself (reconciliation) in Christ and so because of this, we are united together as the church, in Christ.

This is in effect the TL:DR.  Now, each passage and chapter will be rich in meaning and application that will take us deeper.  However, we should be able to see this common thread working through and so each part of the book will point back to the main theme.