Treasury of Scripture Knowledge
The nakedness of thy sister, the daughter of thy father, or the daughter of thy mother, whether born at home, or born abroad, even their nakedness thou shalt not uncover.
And if a man shall take his sister, his father's daughter, or his mother's daughter, and see her nakedness, and she see his nakedness; it is a shameful thing; and they shall be cut off in the sight of the children of their people: he hath uncovered his sister's nakedness; he shall bear his iniquity.
2 Samuel 13:1
And it came to pass after this, that Absalom the son of David had a fair sister, whose name was Tamar; and Amnon the son of David loved her.
And one hath committed abomination with his neighbor's wife; and another hath lewdly defiled his daughter-in-law; and another in thee hath humbled his sister, his father's daughter.