Hugh Nibley has suggested that this passage was punctuated incorrectly by the 1830 typesetter. The first nevertheless-clause is completed by the final main clause, thus “because those miracles were worked by small means … they were slothful and forgat to exercise their faith and diligence”. This interpretation means that the second nevertheless-clause should be treated as a parenthetical one; that is, the second nevertheless-clause should be surrounded by either dashes or parentheses:
Under this interpretation, there was no need for Joseph Smith’s removal of the second nevertheless in his editing for the 1837 edition. The 1830 typesetter had placed a period at the end of the second nevertheless-clause, which made it impossible for the first nevertheless-clause to achieve closure. For discussion of Nibley’s proposal, see page 89 of his “The Liahona’s Cousins”, Improvement Era 64/2 (1961).
Summary: Restore the second nevertheless in Alma 37:41 since this instance of nevertheless heads a parenthetical clause (“nevertheless it did shew unto them marvelous works”), which should be punctuated as parenthetical in the standard text; the first nevertheless-clause is completed by the main clause, “they were slothful and forgat to exercise their faith and diligence”.