Leviticus 18:10

10 You may not have sex relations with your son's daughter or your daughter's daughter, for they are part of yourself;

Leviticus 18:10 Meaning and Commentary

Leviticus 18:10

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.

Leviticus 18:10 In-Context

8 And you may not have sex relations with your father's wife: she is your father's.

9 You may not take your sister, the daughter of your father or of your mother, wherever her birth took place, among you or in another country.

10 You may not have sex relations with your son's daughter or your daughter's daughter, for they are part of yourself;

11 Or your father's wife's daughter, the child of your father, for she is your sister.

12 You may not have sex connection with your father's sister, for she is your father's near relation.