These laws relate to the seventh commandment, and, no doubt, are obligatory on us under the gospel, for they are consonant to the very light and law of nature: one of the articles, that of a man's having his father's wife, the apostle speaks of as a sin not so much as named among the Gentiles, Co1 5:1. Though some of the incests here forbidden were practised by some particular persons among the heathen, yet they were disallowed and detested, unless among those nations who had become barbarous, and were quite given up to vile affections. Observe,

I.That which is forbidden as to the relations here specified is approaching to them to uncover their nakedness, Lev 18:6.

1.It is chiefly intended to forbid the marrying of any of these relations. Marriage is a divine institution; this and the sabbath, the eldest of all, of equal standing with man upon the earth: it is intended for the comfort of human life, and the decent and honourable propagation of the human race, such as became the dignity of man's nature above that of the beasts. It is honourable in all, and these laws are for the support of the honour of it. It was requisite that a divine ordinance should be subject to divine rules and restraints, especially because it concerns a thing wherein the corrupt nature of man is as apt as in any thing to be wilful and impetuous in its desires, and impatient of check. Yet these prohibitions, besides their being enacted by an incontestable authority, are in themselves highly reasonable and equitable. (1.) By marriage two were to become one flesh, therefore those that before were in a sense one flesh by nature could not, without the greatest absurdity, become one flesh by institution; for the institution was designed to unite those who before were not united. (2.) Marriage puts an equality between husband and wife. "Is she not thy companion taken out of thy side?" Therefore, if those who before were superior and inferior should intermarry (which is the case in most of the instances here laid down), the order of nature would be taken away by a positive institution, which must by no means be allowed. The inequality between master and servant, noble and ignoble, is founded in consent and custom, and there is no harm done if that be taken away by the equality of marriage; but the inequality between parents and children, uncles and nieces, aunts and nephews, either by blood or marriage, is founded in nature, and is therefore perpetual, and cannot without confusion be taken away by the equality of marriage, the institution of which, though ancient, is subsequent to the order of nature. (3.) No relations that are equals are forbidden, except brothers and sisters, by the whole blood or half blood, or by marriage; and in this there is not the same natural absurdity as in the former, for Adam's sons must of necessity have married their own sisters; but it was requisite that it should be made by a positive law unlawful and detestable, for the preventing of sinful familiarities between those that in the days of their youth are supposed to live in a house together, and yet cannot intermarry without defeating one of the intentions of marriage, which is the enlargement of friendship and interest. If every man married his own sister (as they would be apt to do from generation to generation if it were lawful), each family would be a world to itself, and it would be forgotten that we are members one of another. It is certain that this has always been looked upon by the more sober heathen as a most infamous and abominable thing; and those who had not this law yet were herein a law to themselves. The making use of the ordinance of marriage for the patronizing of incestuous mixtures is so far from justifying them, or extenuating their guilt, that it adds the guilt of profaning an ordinance of God, and prostituting that to the vilest of purposes which was instituted for the noblest ends. But,

2.Uncleanness, committed with any of these relations out of marriage, is likewise, without doubt, forbidden here, and no less intended than the former: as also all lascivious carriage, wanton dalliance, and every thing that has the appearance of this evil. Relations must love one another, and are to have free and familiar converse with each other, but it must be with all purity; and the less it is suspected of evil by others the more care ought the persons themselves to take that Satan do not get advantage against them, for he is a very subtle enemy, and seeks all occasions against us.

II.The relations forbidden are most of them plainly described; and it is generally laid down as a rule that what relations of a man's own he is bound up from marrying the same relations of his wife he is likewise forbidden to marry, for they two are one. That law which forbids marrying a brother's wife (Lev 18:16) had an exception peculiar to the Jewish state, that, if a man died without issue, his brother or next of kin should marry the widow, and raise up seed to the deceased (Deu 25:5), for reasons which held good only in that commonwealth; and therefore now that those reasons have ceased the exception ceases, and the law is in force, that a man must in no case marry his brother's widow. That article (Lev 18:18) which forbids a man to take a wife to her sister supposes a connivance at polygamy, as some other laws then did (Exo 21:10; Deu 21:15), but forbids a man's marrying two sisters, as Jacob did, because between those who had before been equal there would be apt to arise greater jealousies and animosities than between wives that were not so nearly related. If the sister of the wife be taken for the concubine, or secondary wife, nothing can be more vexing in her life, or as long as she lives.

Any that is near of kin - כל שאר בשרו col shear besaro, any remnant of his flesh, i.e., to any particularly allied to his own family, the prohibited degrees in which are specified from the 7th to the 17th verse (Lev 18:7-17) inclusive. Notwithstanding the prohibitions here, it must be evident that in the infancy of the world, persons very near of kin must have been joined in matrimonial alliances; and that even brothers must have matched with their own sisters. This must have been the case in the family of Adam. In these first instances necessity required this; when this necessity no longer existed, the thing became inexpedient and improper for two reasons:

1.That the duties owing by nature to relatives might not be confounded with those of a social or political kind; for could a man be a brother and a husband, a son and a husband, at the same time, and fulfill the duties of both? Impossible.

2.That by intermarrying with other families, the bonds of social compact might be strengthened and extended, so that the love of our neighbor, etc., might at once be felt to be not only a maxim of sound policy, but also a very practicable and easy duty; and thus feuds, divisions, and wars be prevented.

The nakedness of thy sister,.... To lie with one in so near a relation is exceeding criminal, and for which the law curses a man, Deu 27:22; and to marry her is not lawful; for though it was necessary for the propagation of mankind that a man should marry his sister, for who else could Cain and Abel marry? yet afterwards, when there was an increase of mankind, and there were people enough remote from each other, it became unlawful for persons in such near ties of consanguinity to marry with each other; though the Egyptians did, in imitation of Isis and Osiris (e), and so the Persians, following the example of Cambyses (f):

the daughter of thy father, or the daughter of thy mother; whether she is a sister both by father and mother's side, or whether only by the fathers side and not the mother's, as Sarah was to Abraham, Gen 20:12; or only by the mother's side and not the father's:

whether she be born at home or born abroad; not whether born and brought up in his and her father's house, or born and brought up in another place and province; though there were some, as Aben Ezra observes, that so interpreted it, according to the sense of the word in Gen 50:23; but rather the sense is, as that writer gives it, whether born according to the law of the house of Israel, after espousals and marriage, or without it; that is, whether begotten in lawful marriage or not, whether a legitimate offspring or spurious, born in adultery and whoredom, whether on the father or mother's side; so the Targum of Jonathan, whom thy father begat of another woman, or of thy mother, or whom thy mother bore or brought forth, of thy father, or of another man; and to the same purpose Onkelos:

even their nakedness thou shalt not uncover; neither lie with, or have carnal knowledge of, nor marry one or the other.

(e) Diodor. Sicul. l. 1. p. 23. (f) Herodot. Thalia, sive, l. 3. c. 31.

None of you shall approach to any that is near of kin to him--Very great laxity prevailed amongst the Egyptians in their sentiments and practice about the conjugal relation, as they not only openly sanctioned marriages between brothers and sisters, but even between parents and children. Such incestuous alliances Moses wisely prohibited, and his laws form the basis upon which the marriage regulations of this and other Christian nations are chiefly founded. This verse contains a general summary of all the particular prohibitions; and the forbidden intercourse is pointed out by the phrase, "to approach to." In the specified prohibitions that follow, all of which are included in this general summary, the prohibited familiarity is indicated by the phrases, to "uncover the nakedness" [Lev 18:12-17], to "take" [Lev 18:17-18], and to "lie with" [Lev 18:22-23]. The phrase in this sixth verse, therefore, has the same identical meaning with each of the other three, and the marriages in reference to which it is used are those of consanguinity or too close affinity, amounting to incestuous connections.