Ecclesiastes 12:3

In the day when the keepers of the house - The Body of man is here compared to a House: - mark the metaphors and their propriety.

1. The keepers shall tremble - the hands become paralytic, as is constantly the case, less or more, in old age.

2. The strong men shall bow - The legs become feeble, and unable to support the weight of the body.

3. The grinders cease because they are few - The teeth decayed and mostly lost; the few that remain being incapable of properly masticating hard substances or animal food. And so they cease; for soft or pulpy substances, which are requisite then, require little or no mastication; and these aliments become their ordinary food.

4. Those that look out of the windows - The optic nerves, which receive impressions, through the medium of the different humours of the eye, from surrounding objects - they are darkened; the humours becoming thick, flat, and turbid, they are no longer capable of transmitting those images in that clear, distinct manner, as formerly. There may be an allusion here to the pupil of the eye. Look into it, and you will see your own image in extreme minature looking out upon you; and hence it has its name pupillus, a little child, from pupus, a baby, a doll; because the image in the eye resembles such. The optic nerve being seated at the bottom of the eye, has the images of surrounding objects painted upon it; it looks out through the different humors. The different membranes and humours which compose the eye, and serve for vision, are, the tunica conjunctiva, the tunica sclerotica, the cornea, the iris, the pupil, the choroides, and the retina. The iris is perforated to admit the rays of light, and is called the pupil; the retina is a diffusion of the optic nerve in the bottom of the eye, on which the images are painted or impressed that give us the sensation we term sight or vision. All these membranes, humours, and nerves, are more or less impaired, thickened, or rendered opaque, by old age, expressed by the metaphor, "Those that look out of the windows are darkened."

The body in old age and death is here described under the figure of a decaying house with its inmates and furniture.

This verse is best understood as referring to the change which old age brings to four parts of the body, the arms ("the keepers"), the legs ("the strong men"), the teeth ("the grinders"), and the eyes.

12:3 The house - Of the body: whose keepers are the hands and arms, which are man's best instruments to defend his body; and which in a special manner are subject to his trembling. The strong men - The thighs and legs, in which the main strength of the body consists. Grinders - The teeth, those especially which are commonly so called, because they grind the meat. Cease - To perform their office. And those, &c. - The eyes.By windows he understands either the eye - lids, which like windows, are either opened or shut: or, those humours and coats of the eyes, which are the chief instruments by which we see.