Here we may wonder whether the phrase “because of their faith” should belong to the preceding or the following clause. The 1830 typesetter attached this phrase to the following clause by placing a period after “the simpleness of their words”. All subsequent editions have followed this punctuation.
As already discussed under 1 Nephi 18:17–18, there are a few cases where we need to examine whether a because-of phrase should begin a sentence. Here in 2 Nephi 3:20–21, the because-of phrase seems most appropriately to be identified with the following clause because of the proximity of the connection (“because of their faith their words shall proceed forth”). If the because-of clause is attached to the preceding clause, then we would have the reading “their cry shall go forth … because of their faith”, with the intervening “even according to the simpleness of their words” interrupting the connection between the main clause and the because-of phrase. Since the current punctuation works well enough, there is no good reason to emend the punctuation and thereby create a rather awkward construction.
Summary: Maintain the current punctuation in 2 Nephi 3:20–21; the because-of clause appears to be attached to the following clause, not the preceding one.