"Lythly" has nothing to do with either current meaning of "loathly" ("hideous," or "reluctantly").

The modern English form of the medieval word is "lithely" (adv. of "lithe"), and in Middle English it meant "mildly," among semantically related things.

If "earnestly" is one of them (my dictionary isn't handy) then either or both would do: "earnestly but mildly," i.e., not to scold but to suggest. (I still prefer "mildly": Joseph's words are earnest enough without having to say so specifically.)

BTW, I read "worn" simply as a third-person plural subjunctive : "Come along, Mary, that we were in yon city." (The more usual form, if I recall from grad school, was "woren.")

"That we were" is still understandable in Modern English to some of us, but pretty archaic in these parts.