This passage begins with a past-tense verb form, commanded, but then the (original) text moves into a present-tense description of Alma’s welfare program. The modal verb should is used five times, but in an historical present-tense sense rather than as a conditional modal. Originally the present-tense verb form hath occurred three times in this passage, but for the 1837 edition Joseph Smith changed these cases of hath to the past-tense form had. Consistent with this editing, he could have also changed the subjunctive have in “if he have more abundantly” to the indicative past-tense had (but he did not). Although the 1841 British edition made the change to had, subsequent editions have retained the original subjunctive have. For further discussion regarding the use of the subjunctive in if-clauses, see under subjunctive in volume 3.
These attempts to shift the passage into the past tense can also be seen as consistent with the use of the past-tense commanded at the beginning of the passage as well as the past-tense stood that occurs near the end of this passage (“to those priests that stood in need”). However, the repeated use of should impart, should be required, and should be given gives a distinct presenttense sense to the central part of this passage, thus permitting the use of the present-tense hath and the subjunctive have. The critical text will restore these three original occurrences of hath and will maintain the subjunctive have.
Summary: Restore in Mosiah 18:27–28 the original multiple use of the present-tense hath; such usage is supported by surrounding occurrences of the modal verb should; also maintain the original subjunctive have in the if-clause.