The 1830 typesetter accidentally replaced the plural sins (in the prepositional phrase “in sins and iniquities”) with the singular sin. The 1858 Wright edition (which the RLDS textual tradition follows) restored the plural sins, probably unintentionally. As discussed under Mosiah 29:30–31, in phrases conjoining sin /sins and iniquity /iniquities, the original text always shows number agreement. In Alma 37:10, the critical text will restore the original plural sins in the conjunctive phrase “in sins and iniquities”.
Summary: Restore in Alma 37:10 the plural sins in the phrase “in sins and iniquities”, the reading of the earliest extant source (the printer’s manuscript).