Wikipedia states that: “It is generally accepted that a garbled sentence during the duke’s opening speech represents a place where a line has been lost, possibly due to a printer’s error.” It goes on to aver that because the folio is our only source for the play, there is no possibility of recovering that lost line. Here is the speech which starts at line 3.
Of government the properties to unfold
Would seem in me to affect speech and discourse
Since I am put to know that your own science
Exceeds in that the lists of all advice
My strength can give you. Then no more remains
But that, to your sufficiency, as your worth is able,
And let them work.
In any of the Norton Shakespeare editions it comments that: “The referent of them is unclear. Perhaps a line is missing.” This edition is looking to qualify which persons are are being referred to in the last line And let them work. But this is a misunderstanding of the complete usage of the word them.
If we lookup the definition of them in the Merriam Webster, it may clear up the confusion.
Them: used to refer to certain people, animals, or things as the objects of a verb or preposition
: him or her
To your sufficiency and As your worth is able are prepositional phrases, and Sufficiency and Worth are the objects of the two prepositional phrases. If we replace Them in line 9 with Those from the Webster definition [a reasonably fair substitution in English Grammar] it makes perfect sense. Now we are not looking for a Who as with Them but a What as with Those. The referent is crystal clear as he is simply saying let your sufficiency and worth work for you.
Just because the first folio may seem opaque to us as modern readers, we shouldn’t “jump to conclusions” about there being mistakes in the mother text until we have exhausted every possible reading. The compositor of this play, Ralph Crane, is the same one that gave us The Tempest, a very reliable text. Shakespeare used conventions that authors at the time considered grammatical heresy, but he still managed to become the immortal author that he did…not merely in the English language but in every living language extant in the Globe.