Joyce Carol Oates uses this quote, part of a young girl's guiding principles to ‘ladylike' mannerism:
Be good, sweet maid, and let who will be clever!
(p. 62, ‘The Accursed')
The exclamation mark seems to indicate that, in Oates' mind, it is a complete sentence.
Is it? Doesn't the verb ‘let' need to be completed with another verb? as in, for instance:
Be good, sweet maid, and let be clever who will !
Be good, sweet maid, and let who will be clever be !
The Charles Kingsley's version though, is like this:
Be good, sweet maid, and let who will be clever;
Do noble things, not dream them, all day long:
And so make life, death, and that vast for-ever
One grand, sweet song.
Therein lies the possibility of ‘let…do noble things' -But only if there were no semicolon! As is, Kingsley also appears to terminate the sentence same as Oates. Especially because ‘Be good…' and ‘Do noble…' appear to parallel each other, each beginning a command to the girl.
My point is: whatever the correct interpretation, and whether good the grammar, there is a small cloud of ambiguity over this masterful poem, but bothersome enough to make the reader stop to wonder about the intention of the poet, thus preventing a full appreciation of the considerable beauty of it. Y'all agree? If not why?
My mind parses the line a different way from you. I see the last part as let {someone} be clever, where {someone} is (the person or persons) who will. If you must have another verb in there, make it another be immediately before the one that's already there, but that makes the person reading it sound like Porky Pig, so best to omit it.
My parsing is like Ron's.
In fact, the whole line seems a contrast, "Be good, sweet maid, but let another--not you be clever!" maybe indicating that being clever is not being good. In addition, it seems advice to not even try to stop those who will themselves to be clever.
I agree with Ron and Emmett. The sentence is clipped and poetic and somewhat inverted. And it doesn't help that it contains a subjunctive verb.
Be good, sweet maid, and let be clever who will !
"Be good" is an imperative, more in the tone of advice in this case. "Sweet maid" is the young lady being addressed. "Who will" is a nominal relative with a subjunctive. It might be paraphrased as "whoever might want that." So the remaining part could be paraphrased as "let whoever might want that be clever."
I don't see this as being a strict opposition between "good" and "clever," but there is a strong implication in this advice that cleverness can possibly undermine goodness, and that goodness is the more valuable quality.