A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
deu 24:1OF DIVORCES. (Deu. 24:1-22)
When a man hath taken a wife, and married her, and it come to pass that she find no favour in his eyes--It appears that the practice of divorces was at this early period very prevalent amongst the Israelites, who had in all probability become familiar with it in Egypt [LANE]. The usage, being too deep-rooted to be soon or easily abolished, was tolerated by Moses (Mat 19:8). But it was accompanied under the law with two conditions, which were calculated greatly to prevent the evils incident to the permitted system; namely: (1) The act of divorcement was to be certified on a written document, the preparation of which, with legal formality, would afford time for reflection and repentance; and (2) In the event of the divorced wife being married to another husband, she could not, on the termination of that second marriage, be restored to her first husband, however desirous he might be to receive her.
deu 24:5When a man hath taken a new wife, he shall not go out to war--This law of exemption was founded on good policy and was favorable to matrimony, as it afforded a full opportunity for the affections of the newly married pair being more firmly rooted, and it diminished or removed occasions for the divorces just mentioned.
deu 24:6No 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.
deu 24:7If a man be found stealing any of his brethren--(See Exo 21:16).
deu 24:8Take heed in the plague of leprosy--(See Lev 13:14).
deu 24:10When thou dost lend thy brother anything, thou shalt not go into his house to fetch his pledge--The course recommended was, in kind and considerate regard, to spare the borrower's feelings. In the case of a poor man who had pledged his cloak, it was to be restored before night, as the poor in Eastern countries have commonly no other covering for wrapping themselves in when they go to sleep than the garment they have worn during the day.
deu 24:14Thou shalt not oppress an hired servant that is poor and needy--Hired servants in the East are paid at the close of the day; and for a master to defraud the laborer of his hire, or to withhold it wrongfully for a night, might have subjected a poor man with his family to suffering and was therefore an injustice to be avoided (Lev 19:13).
deu 24:16The fathers shall not be put to death for the children--The rule was addressed for the guidance of magistrates, and it established the equitable principle that none should be responsible for the crimes of others.
deu 24:19When thou cuttest down thine harvest in thy field--The grain, pulled up by the roots or cut down with a sickle, was laid in loose sheaves; the fruit of the olive was obtained by striking the branches with long poles; and the grape clusters, severed by a hook, were gathered in the hands of the vintager. Here is a beneficent provision for the poor. Every forgotten sheaf in the harvest-field was to lie; the olive tree was not to be beaten a second time; nor were grapes to be gathered, in order that, in collecting what remained, the hearts of the stranger, the fatherless, and the widow might be gladdened by the bounty of Providence.