Here we have two that-clauses that initially in 𝓟 had no and separating them. Virtually immediately Oliver Cowdery supralinearly inserted an ampersand; the ink flow is uneven, but it is the same as the ink flow for the immediately preceding correction of obtained to retained (see the previous discussion). Oliver’s correction here probably occurred when he proofed 𝓟 against 𝓞. Either reading, with or without the and, is possible, so the original text probably had the and. The critical text will assume as much. For other cases where Oliver initially omitted the and between that-clauses, see the discussion under Alma 30:35.
Summary: Maintain in Alma 60:24 the and that Oliver Cowdery inserted in 𝓟 (the earliest extant source) between the two that-clauses.