Lev 18:9-11 | KD | STEP | By the sister, the daughter of father or mother, we are to understand only the step-or half-sister, who had either the same father or the same mother as the brother had. The clause, “ whether born at home or born abroad, ” does not refer to legitimate or illegitimate birth, but is to be taken as a more precise definition of the words, daughter of thy father or of thy mother, and understood, as Lud. de Dieu supposes, as referring to the half-sister “of the first marriage, whether the father’s daughter left by a deceased wife, or the mother’s daughter left by a deceased husband,” so that the person marrying her would be a son by a second marriage. Sexual intercourse with a half-sister is described as חסד in , and threatened with extermination. This word generally signifies sparing love, favour, grace; but here, as in , it means dishonour, shame, from the Piel חסּד, to dishonour.

‏ Leviticus 18:9-11

By the sister, the daughter of father or mother, we are to understand only the step-or half-sister, who had either the same father or the same mother as the brother had. The clause, “whether born at home or born abroad,” does not refer to legitimate or illegitimate birth, but is to be taken as a more precise definition of the words, daughter of thy father or of thy mother, and understood, as Lud. de Dieu supposes, as referring to the half-sister “of the first marriage, whether the father’s daughter left by a deceased wife, or the mother’s daughter left by a deceased husband,” so that the person marrying her would be a son by a second marriage. Sexual intercourse with a half-sister is described as חסד in Lev 20:17, and threatened with extermination. This word generally signifies sparing love, favour, grace; but here, as in Pro 14:34, it means dishonour, shame, from the Piel חסּד, to dishonour. Lev 18:10

The prohibition of marriage with a granddaughter, whether the daughter of a son or daughter, is explained in the words, “for they are thy nakedness,” the meaning of which is, that as they were directly descended from the grandfather, carnal intercourse with them would be equivalent to dishonouring his own flesh and blood. Lev 18:11

“The daughter of thy father’s wife (i.e., thy step-mother), born to thy father,” is the half-sister by a second marriage; and the prohibition refers to the son by a first marriage, whereas Lev 18:9 treats of the son by a second marriage. The notion that the man’s own mother is also included, and that the prohibition includes marriage with a full sister, is at variance with the usage of the expression “thy father’s wife.”