Sometimes Bible Translation is a Piece of Cake

Can I use “Bible translation is a piece of cake” to mean that Bible translation is sweet (like cake), but only part of a larger, complete object? English speakers know that the answer is “no.”

The reason it doesn’t work is that “a piece of cake” is an idiom in English, and its meaning doesn’t come from the meaning of the words that comprise it. (For non-English speakers: the phrase means “easy.”) But what would happen if I had to translate something from a language in which “piece of cake” wasn’t an idiom, but — in the case of my translation — a metaphor? Clearly I couldn’t use “piece of cake” in my translation, because the idiomatic meaning would overpower any metaphoric meaning.

I think the same thing has happened over time with some English translations that otherwise would work. For example, “dust and ashes” (though it misses the assonance of the Hebrew) was — I believe — a nice metaphor in the English of the KJV, just as it was probably a nice metaphor in Genesis and Job. But now it’s a common expression. Does that destroy the power of the translation?

What about “daily bread,” also (I think) once a metaphor, now a widespread idiom?

Or what about “salt of the earth,” which is now an idiom that probably doesn’t mean what alas tes ges did?

I’m not sure what can be done, but it seems as though phrases in very successful Bible translations end up becoming idioms, and then because they are idioms, they are no longer successful translations.