As discussed under 1 Nephi 11:1, the original text sometimes uses the verb sit transitively. Here in the printer’s manuscript, we have the past-tense sat instead of the standard set. The 1830 typesetter replaced the original sat with set. The critical text will restore the nonstandard uses, providing they are supported by the earliest textual sources. For a complete discussion of the variation between the verbs sit and set, see sit in volume 3.
Summary: Restore the nonstandard past-tense form sat in Mosiah 10:2.