Alma 5:9 reads in part, "their souls did expand." According to Paul Hoskisson, the context would call for a meaning such as "they became happy," to parallel the phrase in the same verse, "they did sing redeeming love" to celebrate their freedom from the "bands of death" and the "chains of hell." Nowhere in the King James Bible does soul occur in conjunction with the word expand; neither does it occur with the verbs enlarge and swell, each of which accompany soul once in the Book of Mormon (Alma 32:28 and 34 respectively). . . . The Oxford English Dictionary under soul gives no evidence of the phrase "their souls did expand" occurring in English; neither are there usages of enlarge and swell with soul. This and other evidence appears to indicate that the phrase "expand the soul" does not have its origin in English. . . .
It is interesting that one translation of the Semitic word for "liver," etc, is "soul." . . . In Semitic languages related to Hebrew (closely, Ugaritic; and more distantly, Akkaadian) "the liver expands (with feeling)" can be translated "the soul expands with feeling." [Paul Y. Hoskisson, "Textual Evidences for the Book of Mormon," in The Book of Mormon: First Nephi, The Doctrinal Foundation, pp. 284-286]