The answer to this question lies in the story of Abraham and his descendants. While it might seem shocking by modern standards, Abraham's son, Isaac, married his half-sister Rebecca, according to the book of Genesis in the Bible.
Though they shared the same father, Abraham, Isaac and Rebecca were born of different mothers. Isaac's mother was Sarah, Abraham's wife, while Rebecca was the daughter of Abraham's other wife, Keturah.
This practice of marrying a half-sister was not unusual in those times. It was considered acceptable within certain cultural and societal norms. However, it's crucial to remember that cultural and social norms have evolved significantly over time.
The story of Isaac and Rebecca highlights the complexities of family relationships and the importance of understanding the cultural context of historical events.
