The titles "Psalms" and "Psalter" come from the Septuagint (the pre-Christian Greek translation of the OT), where they originally referred to stringed instruments (such as harp, Lyre and lute), then to songs sung with their accompaniment . The traditional Hebrew title is tehillin (meaning "praises" Ps 145), even though many of the psalms are tephillot (meaning "prayers"). In fact, one of the first collections included in the book was titled "the prayers of David son of Jesse" (72:20).
The Psalter is a collection of collections and represents the final stage in a process that spanned centuries. It was put into its final form by postexilic temple personnel, who completed it probably in the third century B.C. As such, it has often been called the prayer book of the ''second" (Zerubbabel's and Herod's) temple and was used in the synagogues as well. But it is more than a treasury of prayers and hymns for liturgical and private use on chosen occasions. Both the scope of its subject matter and the arrangement of the whole collection strongly suggest that this collection was viewed by its final editors as a book of instruction in the faith and in full-orbed godliness—thus a guide for the life of faith in accordance with the Law, the Prophets and the canonical wisdom literature. By the first century A.D. it was referred to as the "Book of Psalms" (Lk 20:42; Ac 1:20). At that time Psalms ,-appears also to have been used as a title for the entire section of the Hebrew OT canon more commonly known as the "Writings" (see Lk 24:44 ).
Many collections preceded this final compilation of the Psalms. In fact, the formation of psalters probably goes back to the early days of the first (Solomon's) temple (or even to the time of David), when the temple liturgy began to take shape. Reference has already been made to "the prayers of David." Additional collections expressly referred to in the present Psalter titles are: (1) the songs and/or psalms "of the Sons of Korah" (Ps 42-49; 84-85; 87-88), (2) the psalms and/or songs "of Asaph" (Ps 50; "13-83) and (3) the songs "of ascents" (Ps 120-134).
Other evidence points to further compilations. Ps 1-41 (Book make frequent use of the divine name Yahweh ("the LORD"), while Ps 42-72 (Book II) make frequent use of Elohim ("God").The reason for the Elohim collection in distinction from the Yahweh collection remains a matter of speculation. Moreover, Ps 93-100 appear to be a traditional collection (see "The LORD reigns" in 93:1; 96:10; 97:1; 99:1). Other apparent groupings include Ps 111-118 (a series of Hallelujah psalms; see introduction to Ps 113), Ps 138-145 (all of which include "of David" in their titles) and Ps 146-150 (with their frequent "Praise the LORD". Whether the "Great Hallel" (Ps 120-136) was already a recognized unit is not known. In its final edition, the Psalter contained 150 psalms. On this the Septuagint (the pre-Chris-tian Greek translation of the OT) and Hebrew texts agree, though they arrive at this number differently. The Septuagint has an extra psalm at the end (but not numbered separately as 151); it also unites Ps 9-10 (see NIV text note on P59) and Ps 114-115 and divides Ps 116 a Ps 147 each into two psalms. Strangely, both the Septuagint and Hebrew texts number 42-43 as two psalms whereas they were evidently originally one (see Ps 42)
In its final form the Psalter was divided into five Books (Ps 1-41; 42-72; 73-89; 90-1 107-150), each of which was provided with a concluding doxology (see 41:13; 72:18-1 89:52; 106:48; 150). The first two of these Books, as already noted, were probably preexilic.The division of the remaining psalms into three Books, thus attaining the number five, was possibly in imitation of the five books of Moses (otherwise known simply as the Law). At least o of these divisions (between Ps 106-107) seems arbitrary (see introduction to Ps 107). In spite of this five-book division, the Psalter was clearly thought of as a whole, with an introductio (Ps 1-2) and a conclusion (Ps 146-150). Notes throughout the Psalms give additional indications of conscious arrangement.
Of the 150 psalms, only 34 lack superscription of any kind (only 17 in the Septuagint, the pre-Christian Greek translation of the OT). These so-called "orphan" psalms are found mainly in Books III-V, where they tend to occur in clusters: Ps 91, 93-97; 99, 104-107; 111-119; 135-137; 146-150. (In Books I-II, only Ps1-2; 10; 33; 43; 71 lack titles, and Ps 10; 43 are actually continuations of the preceding psalms.)
The contents of the superscription vary but fall into a few broad categories: (1) author, (2) name of collection, (3) type of psalms, (4) musical notation, (5) liturgical notations and (6) brief indications of occasion for composition.
Students of the Psalms are not agreed on the antiquity and reliability of these superscription. That many of them are at least preexilic appears evident from the fact that the Septuagint translators were sometimes unclear as to their meaning. Furthermore, the practice of attaching titles, including the name of the author, is ancient. On the other hand, comparison between the Septuagint and the Hebrew texts shows that the content of some titles was still subject to change well into the postexilic period. Most discussion centers on categories 1 and 6 above.
As for the superscriptions regarding occasion of composition, many of these brief notations of events read as if they had been taken from 1,2 Samuel. Moreover, they are sometimes not easily correlated with the content of the psalms thay head. The suspicion therefore arises that they are later attempts to fit the psalms into the real-life events of history. But then why the limited number of such notations, and why the apparent mismatches? The arguments cut both ways.
Regarding authorship, opinions are even more divided. The notations themselves are ambiguous since the Hebrew phraseology used, meaning in general "belonging to," can also be taken in the sense of "concerning" or "for the use of" or "dedicated to." The name may refer to the title of a collection of psalms that had been gathered under a certain name (as "Of Asaph" or "Of the Sons of Korah"). To complicate matters, there is evidence within the Psalter that at last some of the psalms were subjected to editorial revision in the course of their transmission. AS for Davidic authorship, there can be little doubt that the Psalter contains psalms composed by that noted singer and musician and that there was at one time a "Davidic" plaster. This, however, may have also included psalms written concerning David, or concerning one of the latter Davidic kings, or even psalms written in the manner of those he authored. It is also true that the tradition as to which psalms are "Davidic" remains somewhat indefinite, and some "Davidic" psalms seem clearly to reflect later situations. Moreover, "David" is sometimes used elsewhere as a collective for the kings of his dynasty, and this could also be true in the psalms titles.
The word Selah is found in 39 psalms, all but two of which (Ps 140; 143, both "Davidic") are in Books I-III. It is also found in Hab 3, a psalm-like poem. Suggestions as to its meaning abound, but honesty must confess ignorance. Most likely, it is a liturgical notation. The common suggestions that it calls for a brief musical interlude or for a brief liturgical response by the congregation are plausible but unproven (the former may be supported by the Septuagint rendering). In some instances its present placement in the Hebrew text is highly questionable.