One may wonder here if the text originally read “in the flesh”. Elsewhere in the Book of Mormon, there are instances of flesh without a determiner, but each of these is combined with a word that refers to the physical body:
“the arm of flesh” 2 Nephi 4:34 (two times)
“maketh flesh his arm” 2 Nephi 4:34, 2 Nephi 28:31
“flesh and blood” Mosiah 7:27, Ether 3:6, Ether 3:8, Ether 3:9
“this body of flesh” 3 Nephi 28:15
Otherwise the Book of Mormon text modifies flesh with a determiner, usually the, as in the following nearby examples in Abinadi’s discourse:
Except for Mosiah 15:2, Christ’s earthly ministry is referred to as occurring “in the flesh”, not “in flesh”:
The example from Enos 1:8 is particularly appropriate for this discussion since in the printer’s manuscript Oliver Cowdery initially dropped the definite article the. This error in 𝓟 thus supports the possibility that a the might have been accidentally dropped from Mosiah 15:2. (For further discussion, see under Enos 1:8.)
In contrast to the case of “to dwell in flesh” in Mosiah 15:2, the text elsewhere has only examples of “to dwell in the flesh”, but there are only two examples and they both refer to others (rather than Christ) dwelling in the flesh:
Thus the Book of Mormon text supports the use of the in the expression “to dwell in the flesh”. There is, however, one biblical text that refers to Christ taking upon himself a body and dwelling upon the earth:
Of course, the cannot modify flesh in this instance. Nonetheless, the biblical reading makes one wonder if “he dwelleth in flesh”, the earliest reading in Mosiah 15:2, might be possible after all. Consequently, the critical text will maintain the phrase “in flesh”, but with the understanding that it could well have originally read “in the flesh”.
Summary: Maintain in Mosiah 15:2 the earliest (and textually invariant) reading, “and because he dwelleth in flesh he shall be called the Son of God”; this difficult but not impossible reading may have originally read “he dwelleth in the flesh”.