Elsewhere in the text we almost always have the subordinate conjunction that after the past-tense form beheld when there is a following past-tense clause. The only exception in the earliest text is in 1 Nephi 12:11, where the original manuscript reads “and I looked and beheld three generations did pass away in righteousness”. Here in 1 Nephi 12:23 is the only occurrence of beheld that that Joseph Smith edited to beheld. His apparent motivation was to reduce the complexity of having two subordinate that ’s near each other. Yet the text normally has the that when the following clause is in the past tense (see the discussion under 1 Nephi 12:11). In any event, the critical text will restore the that here in 1 Nephi 12:23 since it is found in the earliest textual sources and there is no evidence that its occurrence here is an error.
Summary: Based on the earliest textual sources, restore the subordinate conjunction that after the past-tense form beheld in 1 Nephi 12:23.