Justin Cofer wrote:Exactly what is θεὸς syntactical function here? Is it appositive? Or is it functioning as the predicate?
The old 1885 RV offered no less than four alternate translations of this clause:
"... flesh, who is over all, God blessed for ever."
"... flesh. He who is God over all be/is blessed for ever."
"... flesh. He who is over all is God, blessed for ever."
"... flesh, who is over all. God be/is blessed for ever."
The first was placed in the text, but each of the other three must have had powerful committee advocates, for all three of them to get into the margin.
You'll find an extended discussion of the options, running for several pages of small print, in
Sanday and Headlam.
Of more recent commentaries known to me, the fullest discussion is in Cranfield's ICC, vol. 2, pp. 464-70.