As one studies Isaiah, it is useful to compare the Old Testament version to the Book of Mormon version. In this verse, the Old Testament version lacks the phrase, "or out of the waters of baptism." McConkie and Millett explain the origin of this clause:
"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, and we would also expect to find it in the Joseph Smith Translation of Isaiah 48:1, but we do not.
"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." (McConkie and Millet, Doctrinal Commentary on the Book of Mormon, vol. 1, p. 152)
Baptism was practiced by in Old Testament times as this scripture attests. Other evidence that it was known among the Jews is found in the Dead Sea scrolls:
"…we come upon a series of fragments relating to baptism. By baptism, of course, the reader should realize that the proponents of this literature did not necessarily mean anything different from traditional Jewish ritual immersion. The terminologies are synonymous, though the emphasis on baptismal procedures at Qumran is extraordinary. This can be seen not only in texts such as the one represented by these fragments and the well-known Community Rule,iii,1-4, which in describing baptism makes reference to 'the Holy Spirit', but also the sheer number of ritual immersion facilities at the actual ruins of Qumran." (Robert Eisenman & Michael Wise, The Dead Sea Scrolls Uncovered, p. 230-1)
Further evidence can be inferred from the ministry of John the Baptist. When the scribes and Pharisees came out to see John, none of them ever questioned him about the ordinance of baptism. This must be because the ordinance was familiar to them.
Some have thought that baptism for the dead was performed in the lavers of the tabernacle of Moses and the Temple of Solomon. The latter was founded on the backs of 12 oxen representing the 12 tribes of Israel and is similar to baptismal fonts found in today's temples. However, no ordinances for the dead were performed before the coming of Christ. His ministry in the world of spirits was a necessary prerequisite. Also, the tabernacle of Moses and the Temple of Solomon were temples under the administration of the Aaronic priesthood. All vicarious ordinances are a function of the Melchizedek priesthood and no Melchizedek priesthood ordinances were performed in these temples. There is no evidence that baptisms for the living were performed in these lavers, either. Exodus explains that these were used by the priests as a place to wash their hands and feet prior to entering the tabernacle of the congregation (inner court). See Exodus 30:17-21 and 1 Kings 7:23-6.