This chapter contains a song or psalm, the same with the eighteenth psalm, and which, according to Jarchi, was composed by David in his old age, and, as Kimchi says, at the end or close of his days; but Abarbinel is of opinion that it was written in his youthful time, in the midst of his troubles, and was sung by him as often as he had a deliverance from any; and which may account for the several variations in it from the eighteenth psalm, which, the same writer observes, are seventy four; and are not to be ascribed to the difference of copies, or neglect of copiers: and very probably, towards the close of his days, he revised it, and made it fit for general use, and sent it with the rest of his psalms to the chief musician; but the particular consideration of it, and of the differences in it from Ps 18:1-50 are referred to the exposition of that book in its course.