In the original manuscript, Oliver Cowdery initially wrote “and they went up”, but then he immediately replaced the adverb up with forth (he erased the u, overwrote the p with an f, and then wrote inline the rest of the word, orth. But when Oliver came to copy this passage into the printer’s manuscript, he accidentally dropped this adverb, probably because once more his eye skipped too quickly from the end of a line in 𝓞 to the beginning of the next line. (Oliver made the same mistake in Alma 46:34, skipping a small part of the text at the end of a line in 𝓞; see the discussion under that passage regarding the loss of to do.) For other instances where forth has been lost from the text, if only momentarily, see under Alma 8:21 and Alma 20:28; also see under 2 Nephi 3:20 for the possible loss of forth in the early transmission of that passage.
The expression “to go forth” is very frequent in the Book of Mormon text. In fact, earlier in this verse we have one more example of this usage: “Amalickiah caused that his servants should go forth to meet the king” (Alma 47:22). Thus the use of forth in the original text for the very next clause is fully expected.
Summary: Restore the original occurrence of the adverb forth in Alma 47:22, which means that we get two instances of “to go forth” in this verse (“Amalickiah caused that his servants should go forth to meet the king and they went forth and bowed themselves before the king”).