Augustine of Hippo : Those who assert that sometimes we must lie make inappropriate mention of Abraham as having lied about Sarah whom he called his sister. For he did not say "She is not my wife" but "She is my sister," because Sarah was in fact of a family so closely related that without lying she could be called his sister. This fact Abraham confirmed afterward when Sarah was returned by him who had led her away. Abraham replied to him, saying, "Also she is truly my sister, the daughter of my father, and not the daughter of my mother," that is to say, belonging to his father's family but not to his mother's. Thus he concealed something of the truth but did not say anything false in concealing the fact that she was his wife and in saying that she was his sister. His son Isaac also did this, for we know that he too chose a relative of his as wife. Hence it is not a lie when truth is passed over in silence but when falsehood is brought forth in speech. — Against Lying 10.23