I'm reading this passage and can see how a Calvinist reading it would find support for predestination; i.e., verse 4, God chose us even before the world was founded, and verse 5, God destined us to be Christians.
So, I'm suggesting that you read the Wesleyan view of grace. Here's an introduction to Our Wesleyan Theological Heritage.
In the early church, believers with one kind of background thought themselves superior to those they considered to have a lower background. For those of us moderns who also think of ourselves as superior--or for those of us who have been convinced that we are inferior, we need to remember that both the first to become Christians and the ones who came later are all marked with the seal of the promised Holy Spirit and are God's own people (11-13).
And we need to remember to praise God's glory (14).
After I wrote this, I came across Donald Hayne's excellent discussion of the Calvinist resurgence on the United Methodist Portal page.