When Oliver Cowdery copied this passage from 𝓞 into 𝓟, he initially missed the phrase “again to go to battle”, possibly because his eye skipped from the again to the visually similar against that follows (suggested by David Calabro, personal communication). Virtually immediately, Oliver caught his error and supralinearly inserted the missing phrase in 𝓟 except that he added the word up, writing “again to go up to battle” (all of these words are written without any change in the level of ink flow). But later, probably when he proofed 𝓟 against 𝓞, Oliver crossed out the extra up (the crossout of the up is with heavier ink flow). 𝓞 is not extant here for “again to go (up) to”, but there is no room for the up in the lacuna except by supralinear insertion.
Elsewhere the Book of Mormon text allows either “go to battle” or “go up to battle”, with 10 occurrences with up and 16 without. Nearby we have three examples of the shorter “go to battle”:
Mosiah 10, on the other hand, we get variation:
So it is not surprising that Oliver Cowdery could have initially added an extra up when he copied Alma 47:1. Since either reading is possible, 𝓞 probably read as corrected by Oliver in 𝓟, without the up (“again to go to battle”).
Summary: Accept Oliver Cowdery’s corrected reading in 𝓟 that removed the intrusive up in Alma 47:1, thus giving “go to battle” rather than “go up to battle”.