(Isa. 48:1)
This clause first appeared in the 1840 and 1842 editions of the Book of Mormon. It did not appear again until the 1920 edition, and it has been in all editions since that time. It appears to be a prophetic commentary by Joseph Smith to explain the meaning of the phrase “out of the waters of Judah.” … If this phrase were a restoration of the original text, as found in the more pure version on the brass plates from which it comes, it would have appeared in the 1830 edition of the Book of Mormon… . Through the use of this phrase, Joseph Smith is calling our attention to the fact that the ordinance of baptism was as common to the people of the Old Testament as it was to the people of the Book of Mormon.
(Joseph Fielding McConkie and Robert L. Millet, Doctrinal Commentary on the Book of Mormon, 4 vols. [Salt Lake City: Bookcraft, 1987–1992], 1:151–52.)
The second edition of the Book of Mormon contains an addition not found in the first: “out of the waters of Judah, or out of the waters of baptism.” It is said that Parley P. Pratt suggested the phrase, and certainly Joseph Smith approved it, for it stands in all the early editions after the first. Those added words are not only permissible—they are necessary… . Isaiah did not have to tell his ancient hearers that he had the waters of baptism in mind, but it is necessary to tell it to the modern reader, who without such an explanation would miss the point—for him the translation would be a misleading one without that specification. Where continued revelation is accepted and where all the prophets are speaking the same piece, this sort of thing makes no difficulty at all.
(Hugh W. Nibley, Since Cumorah, 2nd ed. [Salt Lake City: Deseret Book Co., 1988], 133.)
It is interesting that the excavations around the temple site in Jerusalem have revealed numerous baptismal fonts which archaeologists refer to as “ceremonial baths.” Today, the Jewish people have virtually abandoned the rite of baptism, although they have carefully preserved the ritual of circumcision. Significantly, circumcision was given to God’s people in the days of Abraham to remind them of baptism! The Lord said:
“My people have gone astray from my precepts, and have not kept mine ordinances, which I gave unto their fathers;
“And they have not observed mine anointing, and the burial, OR BAPTISM wherewith I commanded them;
“But have turned from the commandment, and taken unto themselves the washing of children, and the blood of sprinkling” (JST, Gen. 17:4–6; emphasis added).
This would suggest that the people were participating in infant baptism and sprinkling their children with blood after the manner of the heathens. The Lord said the ordinance of circumcision was being introduced so that when male children were circumcised on the eighth day, it would remind them that their children were to be baptized in their eighth YEAR. The Lord said that “children are not accountable before me [or eligible for baptism] until they are eight years old” (JST, Gen. 17:11).
(W. Cleon Skousen, Isaiah Speaks to Modern Times [Salt Lake City: The Ensign Publishing Company, 1984], 602.)