The Book of Psalms, or the Psalter, is the great prayer-book of the Church of all times, the collection of divinely inspired odes or songs whose singing was of old accompanied by instruments of music. Under the guidance of God the Psalms as we now know them were at various times collected, five sections, or books, being distinguished (Psa_41:13; Psa_72:18-19; Psa_89:52; Psa_106:48; Psalms 150), the final arrangement being made after the Babylonian Captivity by Ezra, as the tradition of the Jews has it.
To more than one hundred psalms are prefixed inscriptions which give one or more particulars and directions for the public rendering of the sacred song, such as the name of the author, of the instrument on which the accompaniment was to be played, of the style of the music or of the poetry, of the melody which the choirmaster was to choose, of the subject or occasion for which it was written. The "chief musician" was the superintendent of the Temple music, who was probably at the same time the leader of the Temple orchestra and the director of the Temple chorus of priests and Levites.
The Psalter is usually called "The Psalms of David," since he is the only author mentioned in the New Testament, Luk_20:42, and because his name appears in more titles than that of any other writer. The name of David appears in the heading of about one half of the psalms; besides, the authorship of Psalms 2 and Psalms 95 is ascribed to him, Act_4:25; Heb_4:7, He may have written others which are not credited to him. To Asaph, a Levite and one of the three heads of David's choir at Jerusalem, are ascribed twelve psalms; to the sons of Korah, a celebrated family of singers and poets in the time of David, eleven, including Psalms 88, whose author, Heman, belonged to the sons of Korah; to Solomon, two; to Moses, one; and to Ethan, one of the three masters of the Temple music, one.
Of special interest to us are the Messianic psalms, including Psalms 2, 8, 16, 22, 24, 40, 45, 47, 68, 69, 72, 89, 93, 97, 110, 118; they refer to the Messiah, the promised Redeemer of the world, portraying more or less vividly and completely His person and work, His birth, betrayal, agony, and death, His triumph over death, His ascension into heaven and enthronement at the right hand of God the Father Almighty.
Of the general contents of the psalter, Luther writes: "It should be noted that the entire Psalter deals with five subjects; therefore we divide it into five parts. In the first place, some psalms prophesy of Christ and of the Church, or the saints, what would happen to them, etc. ; and to this class belong all the psalms in which there are promises given to the pious and threats to the ungodly. In the second place, there is a number of doctrinal psalms, which teach us what we should do and what omit according to the Law of God; and to this class belong all the psalms which condemn the doctrine of men and extol the Word of God. In the third place, there are several psalms of consolation, which comfort the sorrowing and suffering saints and, on the other hand, condemn and terrify the tyrants. . In the fourth place, there are a few psalms of prayer, in which we pray to God and cry in all distress; and to this class belong all psalms which lament and mourn and cry over the enemies. In the fifth place, we have psalms of thanksgiving, in which we laud and praise God for His various benefits and His assistance; and to this class belong all psalms which praise God in His works, these being the finest and principal psalms. . But we must know that the psalms cannot be just exactly and evenly divided into such parts and verses, for sometimes two, three, and even all five divisions, as noted above, are found in one psalm, so that prophecy, doctrine, consolation, prayer, and thanksgiving are found together. But this division serves for the better understanding of the psalms and that we may the more easily learn and remember them. "