Partially extant evidence from the original manuscript shows that the original text here read “that ye might behold”, not “that ye might be healed”. We have the following in the transcript of 𝓞:
The first three letters of behold are extant at the end of line 30 on this page of 𝓞. The e and the h are definitely connected; that is, there is no space between the e and the h. The phrase be healed was otherwise always spelled by Oliver Cowdery with a space between be and healed (twice in 𝓞 and five times in 𝓟). On the other hand, Oliver virtually always spelled the very frequent behold as one word; only once, in 𝓞 for Alma 57:14, did he spell behold as be hold. If the end of line 30 in 𝓞 read be h rather than beh, then we could not be sure about whether the reading was be healed or behold (although be healed would be favored); but since 𝓞 reads beh, evidence from
Oliver’s spellings strongly supports behold as the reading. At the beginning of the next line of 𝓞 (line 31), the vowel portion (theoretically either o or ea) is missing; the word-final ld is extant. In terms of spacing considerations, the single vowel o fits best, but it is also feasible that Oliver squeezed in two vowels here.
The probability is high that Oliver Cowdery, while copying from the original to the printer’s manuscript, misread behold as be healed since he frequently made errors reading the text at the end of the line in the original manuscript (for a list of examples, see the discussion regarding this versus thus under Alma 11:21). The chances for error are further increased by the preceding occurrence of be healed in the verse (“if ye could be healed by merely casting about your eyes”). For a similar example of manuscript error involving the phrase be healed (although only momentary), see under Alma 15:8.
From a semantic point of view, behold is clearly better here in Alma 33:21. The point of this sentence is to emphasize the word quickly; that is, the text means to say, “if you could be healed by just looking, would you not look quickly?” On the other hand, the current reading, based on 𝓟, is wholly redundant and unnecessary: “if ye could be healed by merely casting about your eyes that ye might be healed”. The critical text, following the partially extant reading in 𝓞 as well as the internal evidence, will restore the original behold here in Alma 33:21.
Summary: In accord with what remains of the original manuscript as well as internal evidence, replace be healed with behold in Alma 33:21: “if ye could be healed by merely casting about your eyes that ye might behold / would ye not behold quickly”.