There is a remarkable resemblance between this psalm and Psalms 14:1-7. Both are ascribed to the same author, David; and each pursues the same line of thought - the folly and wickedness of Atheism. They both show that the belief that there is no God is not a harmless idea, or a mere speculation, but that it has important consequences on the life, and is naturally connected with a wicked life, Psalms 53:3-4.
The difference in the two compositions is (a) in the title; and (b) in the psalm itself.
(a) In the title. Both psalms are ascribed to David, and both are dedicated to the “Chief Musician.” But in the title to the psalm before us, there is this addition: “Upon Mahalath, Maschil.” On the meaning of the term Maschil, see Introduction to Psalms 32:1-11. The term here would seem to imply that the psalm was designed to give instruction on an important subject, but why it is prefixed to this psalm, and not to the others, we have no means of determining. The word, rendered “Mahalath” - מחלת machălath - occurs only here and in the title to Psalms 88. It is supposed by Gesenius to denote a stringed instrument, as a lute or guitar, that was designed to be accompanied with the voice. DeWette renders it “flute.” Luther renders it “for a choir, to be sung by one another;” that is, a responsive choir. The Septuagint and the Latin Vulgate retain the original word with no attempt to translate it. Prof. Alexander renders it disease, because a form of the word “almost identical” occurs Exodus 15:26; Proverbs 18:14; 2 Chronicles 21:15 meaning “disease,” and he supposes reference is to “the spiritual malady with which all mankind are infected, and which is really the theme or subject of the composition.” It is true that there is a word - מחלה machăleh - similar to this, meaning “disease,” but it is also true that the word used here is never employed in that sense, and equally true that such a construction here is forced and unnatural. The obvious supposition is that it refers to an instrument of music.
(b) The difference in the psalms themselves is mainly that in Psalms 53:1-6 Psalms 14:6 is omitted, and that in the other parts of the psalm there are enlargements designed to illustrate or to explain more fully the course of thought in the psalm. It is not known by whom these changes were made. They are, as DeWette remarks, such as could not have occurred by an error in transcribing, and they must have been made by design. Whether the changes were made by the author, or by someone who collected and arranged the psalms, and who, adopting the main thoughts of Psalms 14:1-7, inserted additions conveying new phases of thought, though without intending to supersede the use of the original composition, it is not possible now to determine. It is by no means an improbable supposition that the author of the psalm - David - may have revised it himself, and made these changes as expressing more fully his idea, while, as embodying valuable thoughts, it was deemed not undesirable to retain the original psalm in the collection as proper to be used in the service of God. Similar changes occur in Psalms 18, as compared with 2 Samuel 22, where that psalm occurs in the original form of composition. There is no evidence that the alteration was made by a later writer; we may doubt whether a later writer would alter a composition of David, and publish it under his name.
For an analysis of the psalm, see Introduction to Psalms 14:1-7.