This is what I discovered. And I'm not sure if this has been written about before (most things have, I guess), but I've never heard this interpretation of this passage. The passage is Ephesians 1 starting in verse 3:
Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavenly places,4 even as he chose us in him before the foundation of the world, that we should be holy and blameless before him. In love 5 he predestined us for adoption as sons through Jesus Christ, according to the purpose of his will, 6 to the praise of his glorious grace, with which he has blessed us in the Beloved. 7 In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace, 8 which he lavished upon us, in all wisdom and insight 9 making known to us the mystery of his will, according to his purpose, which he set forth in Christ10 as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth.
So yeah, we're talking about having been "chosen," "predestined" for something- adoption, to the praise of his glorious grace. All this "before the foundation of the world." Then it goes on:
In him we have obtained an inheritance, having been predestined according to the purpose of him who works all things according to the counsel of his will, 12 so that we who were the first to hope in Christ might be to the praise of his glory.
So "we" have obtained an inheritance which was predestined for us, according to the purposes of God. Easy to read as your meat-and-potatoes, predestinarian theology, proving that salvation, or adoption, or hoping in Christ is actually the work of God. Seems to nicely line up as a proof-text for Reformation soteriology. But then....
In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit, 14 who is the guarantee of our inheritance until we acquire possession of it, to the praise of his glory.Did you catch that? "In him you also...." Wait, who's you? Who's he talking about now? It appears that only when verse 13 begins that Paul begins referring to the Ephesians. Well who on earth was he talking about before that?? Why, the apostles themselves, of course. "...we who were the first to hope in Christ..."
He starts the letter by explaining what has happened in Christ through the apostolic witness. These are the predestined ones, the ones who were chosen before the foundation of the world to bear the news of God's reconciliation through Christ to the nations. To "unite all things in him..." The Ephesians are only the object of his description after he's done describing the apostles, and then he stops using the words like "predestined" and "chosen before the foundation of the world."
This is called high ecclesiology. That the pre-planned purpose of God was to unite all things, that means all peoples - Jew and Gentile - into one new people of God, in Christ. This is one of those things that gets screened out when every verse in the Bible gets read as a personal salvation passage, and then discombobulated and placed within the architecture of this or that soteriological framework. Of course predestination has to do with salvation- the salvation of the church, through a message that came to them via the apostles. The apostolic office, the importance of a select few people who alone were given the particular task of being vessels for the Gospel to the world after the Ascension, is one of those nasty little details that protestants like to deal with as little as possible, for fear of being called "catholic" or of endangering sola scriptura.
I'm open to correction on this. But if I'm right, then it's entirely unacceptable to use Ephesians 1 as a defense of Calvinism, the predestination of every little thing that happens (not least salvation), or as a principle on which "grace alone" depends. It refers to the church, through the apostles; the historical inauguration of a new people of God, according to God's eternal purpose, by those who were "eyewitnesses to his majesty." (2 Peter 1:16)
I might add that the use of the word "predestined" in Acts 4:28 seems to be consistent with this. I'll let you look that one up :)
A sort of post-script too. I'm no Greek scholar, but I'm told the word "world" can refer to "age." It's a political word. So to the ancient near easterners, the ascension of Caesar Augustus to the imperial throne was the beginning of a "new world." If that meaning holds true in verse 4, then the choosing that occurs "before the foundation of the world," probably just means the choosing of the apostles, the twelve, by Jesus at the beginning of his ministry. This was indeed before the foundation of God's new age that was inaugurated in Christ's death and resurrection.
I'm going to research this stuff more, probably. So don't take my word for it...