Ahijah could not see, for his eyes were set by reason of his age— The more nearly we examine the structure of the human body, and the more attentively we consider it, the more we are struck with admiration. All, even the hardest parts, as the bones and cartilages, derive their origin from a fluid matter: but in old age the softest membranes grow hard, and the fluids themselves become subject to the laws of petrifaction. The smaller tubes, through which the fluids pass, are tender and flexible in youth, but acquire solidity till the age of perfection; and, at last, in old age harden and even ossify in several parts. Hence the long train of maladies, hence old age, which is itself a malady. The eyes, which are a real camera obscura constructed with infinite art, have not only the faculty of moving in every sense, in children, in adults, and in grown men; but by a certain subtle mechanism, the retina sometimes draws near, sometimes removes from the crystalline, according as the objects are more or less distant: and nature, without our knowing it, and even in spite of us, does in the highest perfection what art effects in a camera obscura, by drawing near, or removing, a paper or cloth from the glass through which the light enters. But in decrepid age this painting naturally goes off, the eyes grow dark, like those of Ahijah, the fibres lose their flexibility, the eyes wrinkle, and at length we see distant objects more distinctly than those which are near; and when the space which is between the retina and crystalline comes to be so blocked up, as that the rays of light can no more centre in this thin tunicle, the person then becomes blind.
Note; (1.) The ministers of God must not be courtiers, but deliver their message to the great, however disagreeable, with boldness and freedom. (2.) Disguises may pass upon men whose dim sight cannot see through the veil; but no covering can hide the hypocrite from the eye of God. (3.) They who hope to recommend themselves to God by their formal duties and services, like Jeroboam's wife with her present, will find a terrible disappointment, when, among hypocrites, their portion shall be allotted in the outer darkness.