The question of being Trinity

Came across a really interesting quote here: Faith and Theology: Robert Jenson and the question of being:
“So what is it to be? … To be God is to anticipate a future self by an inexhaustible interpretive relation to an other that God himself is; to be a creature is to anticipate a future self, by a finite interpretive relation to an other that the creature is not…. Being is interpretive relatedness across time; that is, to be is to rise from the dead. Such is the description of reality that coheres with trinitarian doctrine of God."
I think that a couple of years or so back this was a book that was mentioned in an email group I was on debating outreach to Muslims, in particular explaining the Trinity; one poster was much caught up with the metaphor of identity (though that didn't necessarily preserve them from wandering from the path of trinitarian rectitude!). Hmmm maybe I should get hold of this book.
(From Robert W. Jenson, The Triune Identity: God according to the Gospel (Philadelphia: Fortress, 1982), p. 182.)