The Bible doesn't explicitly state who Cain and Abel married. This has led to various interpretations and theories, primarily rooted in Jewish and Christian traditions:
* Sister Marriage: The most common explanation is that Cain and Abel married their sisters. While this idea can be uncomfortable to modern readers, it's important to remember the context of the early chapters of Genesis. The need to populate the earth was paramount, and in this scenario, marrying siblings would have been seen as the only option. Some argue that genetic concerns were not as relevant in the early generations after creation due to the purported genetic perfection of Adam and Eve.
* Daughters of Adam and Eve Not Mentioned by Name: Genesis 5:4 states that Adam "had other sons and daughters." It is supposed these were daughters of Adam and Eve who were not mentioned in the Bible, and that Cain and Able married.
* Descendants from other Humans: According to the Bible Adam and Eve were the first humans, But other religious manuscripts believe there may have been other human-like species in existence at that time. However, this theory is generally considered unorthodox within mainstream Jewish and Christian belief systems.
It's important to note that none of these explanations are explicitly confirmed by the Bible. The ambiguity surrounding this question reflects the unique and symbolic nature of the early chapters of Genesis.