As discussed under 1 Nephi 8:28, the original text of the Book of Mormon had a number of instances of the historical, now dialectal, prepositional a. Here in Alma 30:56, 58, we have two instances of a begging. In both of these cases, the a was removed in the 1837 edition. For a complete list of such usage, see under prepositional a in volume 3. The critical text will restore all instances of this usage, whenever there is evidence for the a in the earliest textual sources.
We also note here that Joseph Smith, in his editing of 𝓟 for the 1837 edition, deleted the word food in verse 58, perhaps because he wanted to suggest that Korihor might have also been begging for other things for his support (such as clothing). In any event, the 1837 edition and all subsequent editions have ignored this emendation, perhaps because of the previous reference to begging for food in verse 56 (“but he was cast out and went about from house to house a begging for his food”). The critical text, in agreement with all the printed editions, will retain the reference to begging for food in Alma 30:58.
Summary: Maintain in Alma 30:56, 58 the two uses of the prepositional a in a begging; also maintain the two specific references to Korihor begging for food.