Notice that the very first word in this first chapter of Isaiah that Nephi quotes is not hear but hearken—supplementing the passive hearing with active obeying.
In the 1840 printing of the Book of Mormon, the Prophet Joseph Smith added after “the waters of Judah” the phrase “or out of the waters of baptism.” This refers to those who have taken on themselves the covenant of baptism, thus indicating that baptism was an essential ordinance performed in Old Testament times (though known more by the term immersion than by the later Greek term baptism