LogFAQs > #971694876

It was their twin sisters Kalmana and Balbira in Orthodox Jewish oral tradition. The first few generations, humans were born as twin brother and sister. In fact, in one of the oral traditions, Abel's murder was indirectly caused by Cain's lust for his own twin sister.

The story goes that Cain married Abel's twin sister and had children. However, he began to lust after his own unmarried twin and wanted to marry her as well. Adam instructed his feuding sons to each make an offering and whichever one God chose would be the one who would marry Cain's twin.

Abel truly loved Cain's twin, so he sacrificed the best of what he had. Cain didn't bother to sacrifice the best of what he had, he only offered enough to outdo Abel. In the end, God chose Abel because Cain was stingy. Cain was so enraged that he murdered Abel.

When Cain was exiled, his wife and children followed him. Abel never had a chance to have children and all of Cain's lineage drowned. Cain himself died either in or before the flood depending on whichever oral tradition. This left only Seth's lineage to survive into modern times.