The Book of Psalms in the canon of the sacred Scriptures gives to the modern reader an insight into the religious life of the Hebrews that cannot be obtained from any of the other Old Testament writings. Although Jeremiah and some of the other prophets emphasized the inwardness of religion, they did so primarily to counteract the formalism that had become conspicuous in the Temple services and other practices that they observed. In Psalms, the longings, the hopes, the sorrows, and the disappointments of individual worshipers find their clearest expression. Here, we find what the various authors felt even in those situations that they were not able to understand. Although some of the psalms are probably as old as the time of King David, not until a relatively late period was the entire collection gathered and organized in the form in which it has been preserved.
Like other portions of Old Testament literature, the original psalms were edited and supplemented from time to time. Frequently we find evidence of a tendency to add something to a psalm as it first appeared in order to give to it an interpretation that would be more in accord with generally accepted ideas. For example, in Psalm 51, the first seventeen verses are written in the spirit of the great prophets, who insisted that the true worship of Yahweh consists not in sacrifices made on an altar nor in the observance of ritualistic requirements but in the inner attitudes of the human heart. The next two verses of the psalm present a very different idea, for an editor who was evidently under the influence of the post-exilic emphasis on the importance of ritual and ceremony added a statement that was intended to show that the attitude of the human heart was but a prelude to the sacrificing of bulls on the altar. It is not uncommon, even at the present time, to find hymn books that continue to use ancient conceptions, even though these have long been replaced with ideas that are more in harmony with the spirit of the times.
