εἰς is part of an idiom here and can also be translated as "unto."
αὐτῷ ἡ δόξα εἰς τοὺς αἰῶνας, ἀμήν
"(To) him (be) the glory unto the ages, amen."
The idiom is εἰς τοὺς αἰῶνας ("unto the ages") and means "forever."
Source: My years in Koine Greek classes, and I think I also read it in Porter's Idioms of the Greek New Testament.
I think Edwards does a valiant effort of attempting to figure out what would have been a very odd construction. However, I think that the simpler explanation of it being idiom repeated throughout the New Testament by multiple authors is preferable.
The two occurrences of εἰς are cases in point for the flexibility of participles. Sometimes (usually) they're directional, but other times they're used as preverbs, and other times they're idiomatic.
David Allen Black illustrates the differences between the εἰς and en where en is more within, and εἰς is directional toward the containment ("into"). However, εἰς also allows for advantage and could render this "for" leading to "from" -> "through" -> "for."
It seems like the ESV committee chose to emphasize the directional properties of εἰς, dropping the "in" and opting for "to." Edwards seems to focus on the locative function, but that's generally a more common function of en (which would open a whole other realm of exegetical issues, since en can also often note instrumental means and could be rendered "by"). I tend to agree with the NIV interpretation and understand the first εἰς as advantage and the second as idiomatic.