No man shall take the nether. God now enforces another principle of equity in relation to loans, (not to be too strict ) in requiring pledges, whereby the poor are often exceedingly distressed. In the first place, He prohibits the taking of anything in pledge which is necessary to the poor for the support of existence; for by the words which I have translated meta and catillus, i e., the upper and nether millstone, He designates by synecdoche all other instruments, which workmen cannot do without in earning their daily bread. As if any one should forcibly deprive a husbandman of his plough, or his spade, or harrow, or other tools, or should empty a shoemaker's, or potter's, or other person's shop, who could not exercise his trade when deprived of its implements; and this is sufficiently clear from the context, where it is said, "He taketh a man's life to pledge," together with his millstones. He, then, is as cruel, whosoever takes in pledge what supports a poor man's life, as if he should take away bread from a starving man, and thus his life itself, which, as it is sustained by labor, so, when its means of subsistence are cut off, is, as it were, itself destroyed.

Compare Exodus 22:25-26.

The nether or the upper mill-stone - Small hand-mills which can be worked by a single person were formerly in use among the Jews, and are still used in many parts of the East. As therefore the day's meal was generally ground for each day, they keeping no stock beforehand, hence they were forbidden to take either of the stones to pledge, because in such a case the family must be without bread. On this account the text terms the millstone the man's life.

No man shall take the nether or the upper (d) millstone to pledge: for he taketh [a man's] life to pledge.
(d) Not anything by which a man gets his living.

No man shall take the nether or the upper millstone to pledge,.... The first word being of the dual number takes in both stones, wherefore Vatablus renders the words,"ye shall not take for a pledge both the millstones, nor indeed the uppermost;''which is the least; so far should they be from taking both, that they were not allowed to take the uppermost, which was the shortest, meanest, and lightest; and indeed if anyone of them was taken, the other became useless, so that neither was to be taken:
for he taketh a man's life to pledge; or with which his life is supported, and the life of his family; for if he has corn to supply them with, yet if his mill or millstones are pawned, he cannot grind his corn, and so he and his family must starve: and in those times and countries they did, as the Arabs do to this day, as Dr. Shaw (d) relates,"most families grind their wheat and barley at home, having two portable millstones for that purpose; the uppermost whereof is turned round by a small handle of wood or iron, that is placed in the rim;''and these millstones being portable, might be the more easily taken for pledges, which is here forbidden, for the above reason; and this takes in any other thing whatever, on which a man's living depends, or by which he gets his bread (e).
(d) Travels, p. 231. Edit. 2. (e) Misn. Bava Metzia, c. 9. sect. 13.

No man shall take the nether or the upper millstone to pledge--The "upper" stone being concave, covers the "nether" like a lid; and it has a small aperture, through which the corn is poured, as well as a handle by which it is turned. The propriety of the law was founded on the custom of grinding corn every morning for daily consumption. If either of the stones, therefore, which composed the handmill was wanting, a person would be deprived of his necessary provision.

Various Prohibitions. - Deuteronomy 24:6. "No man shall take in pledge the handmill and millstone, for he (who does this) is pawning life." רחים, the handmill; רכב, lit., the runner, i.e., the upper millstone. Neither the whole mill nor the upper millstone was to be asked for as a pledge, by which the mill would be rendered useless, since the handmill was indispensable for preparing the daily food for the house; so that whoever took them away injured life itself, by withdrawing what was indispensable to the preservation of life. The mill is mentioned as one specimen of articles of this kind, like the clothing in Exodus 22:25-26, which served the poor man as bed-clothes also. Breaches of this commandment are reproved in Amos 2:8; Job 22:6; Proverbs 20:16; Proverbs 22:27; Proverbs 27:13.

Mill - stone - Used in their hand - mills. Under this, he understands all other things necessary to get a livelihood, the taking away whereof is against the laws both of charity and prudence, seeing by those things alone he can be enabled both to subsist and to pay his debts. Life - His livelihood, the necessary support of his life.