(10) The nakedness of thy son's daughter. From this prohibition it is inferred that a man must not marry his own daughter. If a granddaughter, who is a degree further removed from him, is proscribed, how much more his own daughter. Hence the canonical law during the second Temple deduced from this passage that "whoso companieth with a woman, even by way of fornication, and begetteth a daughter, she is forbidden to him." Still, when the mother is expressly forbidden to the son (see Leviticus 18:7), it is strange that the daughter should have been passed over in silence, and be left to inference. It is therefore more than probable that a word has dropped out of the text, and that originally it stood here, "the nakedness of thy daughter and of thy son's daughter," &c. That this is not a solitary instance where the text has suffered from disarrangement we shall presently have occasion to see in Leviticus 18:11.

Verse 10. - The fourth case of incest which is prohibited is that with a granddaughter, whether the daughter of son or daughter, for, as they are descended from the grandfather, their's is thine own nakedness.

18:1-30 Unlawful marriages and fleshly lusts. - Here is a law against all conformity to the corrupt usages of the heathen. Also laws against incest, against brutal lusts, and barbarous idolatries; and the enforcement of these laws from the ruin of the Canaanites. God here gives moral precepts. Close and constant adherence to God's ordinances is the most effectual preservative from gross sin. The grace of God only will secure us; that grace is to be expected only in the use of the means of grace. Nor does He ever leave any to their hearts' lusts, till they have left him and his services.The nakedness of thy son's daughter, or of thy daughter's daughter,.... A man might not marry his granddaughter, whether a descendant of his son or of his daughter, nor any further off descending from him in a right line, not his great-granddaughter, and so on; and if he might not marry his granddaughter, much less his own daughter, as Jarchi observes, for the relation is still nearer; therefore that being prohibited, this in course must, though not mentioned:

even their nakedness thou shalt not uncover; neither debauch nor marry such an one:

for theirs is thine own nakedness; which sprung from his, being the descendants either of his son or daughter; the Targum of Jonathan is,"for they are as thy nakedness,''his own flesh and blood.