"An eye for an eye!"
Translation:Auge um Auge!
"um" in this sense is normally used for showing repeated actions. "Schlag um Schlag" (hit), "Fall um Fall" (case). And is translated as "for". But it is not a modern way of using "um". So it only really works in idiomatic contexts. Like here: "Auge um Auge." It means literally that after (hurting) one eye another one follows and so on. It refers to the escalation of conflicts if nobody backs down.
I hope I could be of help.
I don't think that the original Latin phrase (oculum pro oculo) was supposed to mean this. It means that to a person that has done something to another person, there has to be done the same (if you hurt an eye, your eye gonna be hurt too).
But maybe the German translation means exactly what you described.
So it can't work as meeting someone eye to eye?
If it's just two people meeting each other with nobody else, you can say unter vier Augen treffen (meet someone under four eyes).
For talking about speaking face to face, I can think of von Angesicht zu Angesicht, using a slightly dated/poetic word for "face".
I can't think of a "normal" version off the top of my head.
Is the article-full version un-idiomatic?
"Ein Auge um einem Auge" is not accepted.
And that would be an incorrect expansion anyway; um in the meaning of "in exchange for" requires the accusative case, so it would have to be ein Auge um ein Auge.
did Luether object to the use of articles?
I've never heard of that.