Matthew 5:21–22 (King James Bible) and whosoever shall kill shall be in danger of the judgment but I say unto you that whosoever is angry with his brother without a cause shall be in danger of the judgment
Here in verse 22, the Book of Mormon text reads “shall be in danger of his judgment”, while the King James text reads “shall be in danger of the judgment”. One wonders if the determiner his in verse 22 of the Book of Mormon version might be an error for the (the King James reading) since the preceding text reads “whosoever is angry with his brother”. Both 𝓟 and the 1830 edition read “shall be in danger of his judgment”, so 𝓞 probably did too; if there is an error here in the Book of Mormon text, it would have occurred as the text was dictated.
Nonetheless, the Book of Mormon reading will work. For instance, the specific reference to a brother here in verse 22 (“whosoever is angry with his brother”) could mean that this brother might have cause against someone in the day of judgment for having been angry at him. Another possibility, one more plausible in my opinion, is based on the parallelism between the judgment mentioned in verse 21 and the one here in verse 22:
In other words, in the Book of Mormon text the phrase “the judgment” has been revised both times, to “the judgment of God” in verse 21 and to “his judgment” (that is, to God’s judgment) in verse 22. The phrase “his judgment” in verse 22 does not refer to ‘the judgment of a brother’ but to ‘the judgment of God’.
Thus the Book of Mormon reading in verse 22, “his judgment”, may be fully intended under either of these two interpretations: his can refer to one’s brother or, more likely, to God. The critical text will therefore maintain the earliest extant reading in verse 22, “shall be in danger of his judgment”, since it will work.
We note here in passing that in verse 22 there is a significant textual difference between the Book of Mormon reading and the King James text, namely, the omission of the phrase “without a cause”. This phrase is also omitted in some of the earliest New Testament Greek manuscripts, thus providing in this instance support for the Book of Mormon reading. (See the apparatus under Matthew 5:22 in the Nestle-Aland Greek New Testament, Novum Testamentum Graece.) But in general, other textual differences between the Book of Mormon text and the King James version of the Sermon on the Mount are not supported by textual variants in the Greek New Testament text.
Summary: Maintain in 3 Nephi 12:22 the determiner his in “shall be in danger of his judgment”; although the his could be an error for the (the King James reading), this substitution may very well be intended, especially since the previous verse refers to “the judgment of God” in the Book of Mormon text rather than simply “the judgment” (the King James reading in Matthew 5:21).