If the Old Testament is... more than human, we can of course set no limit to the weight or multiplicity of meanings which have been laid upon it. If any writer may say more than he knows (see "Second Meanings") and mean more than he meant, then these writers will be especially likely to do so. And not by accident.
I have therefore no difficulty in accepting, say, the view of those scholars who tell us that the account of Creation in Genesis is derived from earlier Semitic stories which were Pagan and mythical. We must of course be quite clear what “derived from” means. Stories do not reproduce their species like mice. They are told by men. Each re-teller either repeats exactly what his predecessor had told him or else changes it. He may change it unknowingly or deliberately. If he changes it deliberately, his invention, his sense of form, his ethics, his ideas of what is fit, or edifying, or merely interesting, all come in. If unknowingly, then his unconscious (which is so largely responsible for our forgettings) has been at work. Thus at every step in what is called—a little misleadingly—the “evolution” of a story, a man, all he is and all his attitudes, are involved. And no good work is done anywhere without aid from the Father of Lights. When a series of such re-tellings turns a creation story which at first had almost no religious or metaphysical significance into a story which achieves the idea of true Creation and of a transcendent Creator (as Genesis does), then nothing will make me believe that some of the re-tellers, or some one of them, has not been guided by God. Thus something originally merely natural—the kind of myth that is found among most nations—will have been raised by God above itself, qualified by Him and compelled by Him to serve purposes which of itself it would not have served. Generalising thus, I take it that the whole Old Testament consists of the same sort of material as any other literature—chronicle (some of it obviously pretty accurate), poems, moral and political diatribes, romances, and what not; but all taken into the service of God’s word. Not all, I suppose, in the same way. There are prophets who write with the clearest awareness that Divine compulsion is upon them. There are chroniclers whose intention may have been merely to record. There are poets like those in the Song of Songs who probably never dreamed of any but a secular and natural purpose in what they composed. There is (and it is no less important) the work first of the Jewish and then of the Christian Church in preserving and canonising just these books. There is the work of redactors and editors in modifying them. On all of these I suppose a Divine pressure; of which not by any means all need have been conscious.
C.S. Lewis, “Scripture,” Reflections on the Psalms (1958, this excerpt taken from The Essential C.S. Lewis Touchstone, 1998) 402-403. It’s the next chapter, but “Scripture” is very much an application of the chapter “Second Meanings.”