"Who was Cain's wife?" is definitely one of the Top Ten Questions of the Bible. Genesis 4: 1-16 tells a curious story of Adam and Eve's first-born sons Cain and Abel. Several themes appear in this story including sibling rivalry, the attraction of sin, crime and punishment, the futility of pretense before God and the moral distinction between civilization and barbarism. The editor of The Oxford Companion to the Bible Bruce M. Metzgar explains in his essay titled Names for the Nameless that the Bible contains many people with names as well as quite a few who play a part in scripture but are not named. And sometimes there is more than one name attributed to the same person.
At the beginning of the Hebrew Bible readers frequently ask So, who did Cain marry? Metzger explains that the answer is presented in a Jewish manuscript called "The Little Genesis" or also called the Book of Jubilee. The apocryphal text is thought to have been written in second century BCE and according to chapter four verse nine,' after giving birth to Cain and Abel, Eve bore a daughter named Awan, who eventually became Cain's wife.' After the birth of his son Seth, Adam fathered another daughter and named her Azura, who later became Seth's wife. The customary Christian and Jewish answer is that Cain married his sister.
During the earliest times of Israel the institution of marriage is closely linked to kinship in the Hebrew Bible. There are suggestions that marriage was considered an extension of kinship through an informal or written covenant or agreement. The position of women in ancient Israel is a central factor in understanding the foundation of marriage. A woman appears to always to have been under the safeguard and authority of her nearest male kin. Endogamy is the marriage within one's group, however that is possibly defined and exogamy is marriage outside it. Both are demonstrated in the Bible. In the ancestral narratives, endogamy seems to have been the overriding practice. For example in Genesis 24 Abraham sends his servant back to Mesopotamia to find a wife for his son Isaac from among his own kin. 1 Yet exogamy is also accounted by Esau 2 and Joseph 3 The kings of Israel and Judah also practiced exogamy. For example David who had a number of marriages that were endogamous starting with Saul's daughter Michal. 4 5 Solomon and Ahab are also described as having exogamous marriages. The Deuteronomic opinion of exogamy was antagonistic because of the apprehension over apostasy. 6 7 On the other hand the book of Ruth has been understood as adopting a stance in which exogamy is suitable.
In the New Testament Jesus does not present any teachings about marriages but it can be inferred from his thoughts about divorce 8 that he perceived it positively, with monogamy being the model. As in he Hebrew Bible, the marriage relationship is used in the New Testament to describe the bond between the community and God expressed as the church and Christ.
Holy BibleOxford Companion to the Bible, Russell Fuller and Bruce Metzger, authors; Metzger and Coogan, edited by Bruce Metzger and Michael Coogan. New York: Oxford University Press, 1993, p.547-547 and p.496-497.