sides. With none of these may either of the married parties, after the death of the other, cohabit or marry, any more than with the same relatives in blood.
The man therefore who marries the sister of his deceased wife is as much guilty of incest, as if he had married his own sister by blood: for the sister of the
deceased wife has, by his antecedent marriage, become his own sister, and is declared to be such by the law of God.
"The marriage of a wife's sister is, in the eyes of God, the very same with the marriage of one's own sister. When a man marries a woman, 'they are
no more twain,' says God, 'but one flesh:' how? not literally: for their persons are as distinct as ever. Not with respect to their blood relations:
they were that before their marriage. But yet by this marriage, they are made one flesh. The flesh of the husband and wife being thus identified,
they stand in the same relation to each other's sisters and brothers as to their own: i.e. as to the lawfulness of connubial intercourse. So that it is quite as
agreeable to the divine law for a man to marry his own sister, as to marry a sister of his wife." [Christian's Magazine, loc. cit.]
"By marriage the husband and wife are one person in law. Upon this principle of an union of person in husband and wife, depend almost all the
legal rights, duties and disabilities, that either of them acquire by the marriage. - The same degrees of affinity are prohibited. Affinity always arises by
the marriage of one of the parties so related. As a husband is related by affinity to all the consanguinei of his wife, and vice versa the wife to all
the husband's consanguinei: for the husband and wife being considered one flesh, those who are related to the one by blood, are related to the other by affinity.
Therefore a man after his wife's death cannot marry her sister, aunt, or niece." [Blackstone's Com. book 1. chap. 13, and note.]
Whether the prohibited degrees be computed by the scale of the canon or the civil law, the result is the same. Every man of common understanding will confess,
that the sister of a wife is, at least, one degree nearer to the husband, than the aunt, and two degrees nearer than the niece. If God forbids him to marry
the aunt or niece, because they are too near of kin, it is beyond all dispute that he forbids