"... Psalm 18 is not a poorly preserved copy of a written text of 2 Samuel 22; nor is 2 Samuel 22 a copy of Psalm 18. We do not have here a text that was initially preserved in written form in one version and as a copy of that text in the other version. We have two versions of a song - each preserved in writing somewhat independent of the other. The number of alternative readings between the two versions points definitively in that direction ... After the initial reduction of the versions to writing, genetic variants were produced as errors in the copying of the consonantal text. James Barr rightly noted: “One cannot, indeed, assume that all such differences between parallel texts are a result of textual corruption; some may go back to free variants in oral tradition.” Modification within different communities is the model that corresponds most naturally to the data introduced in the earliest (oral) stage. Two lines of evidence support this explanation. First, the presence of differences of pronunciation, morphology, grammar, and word choice suggests that we are looking at more than just a collection of the stylistic preferences of an individual. Second, given the nature of the text—that is, a thanksgiving hymn to be sung and appropriated in worship repeatedly—we might expect that local versions would develop ..."