From Surprised by Joy:
"The Book of Job appears to me unhistorical because it begins about a man quite unconnected with all history or even legend, with no genealogy, living in a country of which the Bible elsewhere has hardly anything to say..." [page 110]
"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....
"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 retellings 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." [page 110-111]
"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. Generalizing this, 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....
"The human qualities of the raw materials show through. Naivety, error, contradiction, even (as in the cursing Psalms) wickedness are not removed.
"We read in Genesis (2, 7) that God formed man of the dust and breathed life into him. For all the first writer knew of it, this passage might merely illustrate the survival, even in a truly creational story, of the Pagan inability to conceive true Creation, the savage, pictorial tendency to imagine God making things 'out of' something as the potter or the carpenter does.
"Nevertheless, whether by lucky accident or (as I think) by God’s guidance, it embodies a profound principle. For on any view man is in one sense clearly made 'out of' something else. He is an animal; but an animal called to be, or raised to be, or (if you like) doomed to be, something more than an animal. On the ordinary biological view (what difficulties I have about evolution are not religious) one of the primates is changed so that he becomes man; but he remains still a primate and an animal. He is taken up into a new life without relinquishing the old." [page 115]
"No one ever attempted to show in what sense Christianity fulfilled Paganism or Paganism prefigured Christianity....." [page 62]
From the last sermon Lewis preached, "A Slip of the Tongue," in 1956. (Published in his 1962 book, A Weight of Glory). Notice the emphasis on spiritual growth through "moral theology, in steady rational thinking, in the advice of good friends and good books...." -- not through reading God's Word:
"We can become scrupulous or fanatical; we can, in what seems zeal but is really presumption, embrace tasks never intended for us. That is the truth in the temptation. The lie consists in the suggestion that our best protection is a prudent regard for the safety of our pocket, our habitual indulgences, and our ambitions. But that is quite false. Our real protection is to be sought elsewhere: in common Christian usage, in moral theology, in steady rational thinking, in the advice of good friends and good books, and (if need be) in a skilled spiritual director." 129-130
From Christian Mythmakers by Rolland Hein (Chicago: Cornerstone, 1998).
"With Tolkien’s help, Lewis came to see ancient pagan mythologies as conveying vestiges of divine power, true indications of the working of the eternal in time. He no longer viewed them as “lies in silver,” unfounded and false in substance (in accordance with the more traditional Christian attitude); they came to be stories that not only suggest the spiritual condition of people but also manifest something of supernatural reality—or mythic truth. 
"One can imagine the excitement Lewis must have felt the
night on Addison’s walk when Tolkien brought that
bear upon him and they talked late into the night. The mystery that had aroused his yearnings since his boyhood [referring to pagan myth] was not enticing lies, but Reality itself. [204-205]
"Lewis at various times attempted, in both prose and action, to define the nature of myth.... One of the functions of true art is to present glimpses of 'what reality may well be like at some more central region.' The emanations of this higher, essential reality that reach to earth, the very atmosphere of glory which is the inevitable concomitant of all supernatural manifestations of the Real, was what Lewis called myth." 
concept of myth, therefore, was markedly different
from that of many in the literary community at large,
who saw it as simply a literary genre, an effort of the
human imagination. With Lewis, myth was a vehicle by
which supernatural reality communicates to man; hence,
he emphasized the extraliterary aspect of his concept. 'What
flows into you from myth is not truth but reality
(truth is always about something, but reality is that
about which truth is), and, therefore, every myth
becomes the father of innumerable truths on the
abstract level.' The flow of energy is from Ultimate
Reality to the individual, not from the individual
imagination upwards." I[205-206]
"As the early Lewis delineated the pattern of Christian conversion from using his own as a model, he viewed it as an intellectual affair, seemingly convinced that a sincere, clear-sighted and informed intellectual striving, motivated by the deep compulsions of desire, will lead one to Christian orthodoxy. In The Allegory of Love, he approved of Albertus Magnus’s view that: 'The real trouble abut fallen man is not the strength of his pleasures but the weakness of his reason'; and in Perelandra he has the Green Lady equate Christ to Reason: 'Since our Beloved became a man, how should Reason in any world take on another form?' she asks. Such thinking strongly echoes Milton’s equation of Christ and Right Reason in Paradise Lost.
"But Lewis’s faith in the efficacy of reason diminished later in his life, when he came to recognize the larger privilege of the imagination in the perception of Higher Reality, and to place yet a stronger emphasis upon myth." 
"The great good, which Maleldil intended in creating Thulcandra and which was lost because of the Fall, is in Perelandra to be realized. It is not a greater good than that of Eden... but an alternative one. After the evil that possesses Thulcandra is obliterated, the Great Dance will proceed. Lewis’s vision of Ultimate Things is sweeping and exhilarating."