I take this to be the greatest poem in the Psalter and one of the greatest lyrics in the world. Most readers will remember its structure: six verses about Nature, five about the Law, and four of personal prayer. The actual words supply no logical connection between the first and second movements. In this way, its technique resembles that of the most modern poetry. A modern poet would pass, with similar abruptness, from one theme to another and leave you to find out the connecting link for yourself. But then, he would possibly be doing this quite deliberately. He might have, though he chose to conceal, a perfectly clear and conscious link in his own mind which he could express to you in logical prose, if he wanted to.
I doubt if the ancient poet was like that. I think he felt, effortlessly and without reflecting on it, so close a connection, indeed (for his imagination) such an identity between his first theme and his second, that he passed from one to the other without realizing that he had made any transition. First, he thinks of the sky, how, day after day, the pageantry we see there shows us the splendor of its Creator. Then, he thinks of the sun, the bridal joyousness of its rising, the unimaginable speed of its daily voyage from east to west. Finally, of its heat: not, of course, the mild heats of our climate, but the cloudless, blinding, tyrannous rays hammering the hills, searching every cranny. The key phrase on which the whole poem depends is “there is nothing hid from the heat thereof.” It pierces everywhere with its strong, clean ardor.
From: Reflections on the Psalms by C. S. Lewis (New York: Harper One, 1958), pp. 73-74.