The Bible opens with one of many mysteries—where did Cain get his wife? Some people think it’s trivia, but it’s not. The gospel is involved.
Here’s the concern: Adam and Eve had Cain and Abel, Cain killed Abel, and then Cain went off and had a family with his wife (Genesis 4:1–17). But where did Cain’s wife come from? It’s an age-old question with at least two distinct gospel consequences.
First, the unbeliever uses this sort of question to dismiss the gospel.
You see, many people today don’t believe the gospel because they don’t believe the book from which the gospel comes. They are convinced that the Bible has been disproved by evolution and its supposed ape-men, rocks that are billions of years old, and so on.
So a question like, “Where did Cain get his wife?” can be a real obstacle for them. If a Christian’s answer is, “I don’t know, but the important thing is to trust in Jesus!” their logical response is, “Why? If the Bible is wrong about history, then why trust what it says about eternal salvation?” The evolutionary view of history undermines the Bible’s authority, including what it says about sin and salvation.
Second, the believer’s response can distort the gospel.
Sadly, many Christians reject the history documented in Genesis and concede that God may have used evolution or created different people groups at the beginning. In that case, Cain’s wife would have come from people not descended from Adam. But this leads to a tragic, unintended gospel distortion. If some people are not descended from Adam, then the gospel is not for all people! Christ had to be made like us, “his brethren,” so He could redeem us (Hebrews 2:17). That means we must be related to Him to be saved.
Thankfully, we are related to Jesus
Christ through our common ancestor
Adam. God’s Word tells us all people
are descendants of Adam, and all people
are sinners by nature and by choice
and are under the judgment of death.
Through one man sin entered the
world, and death through sin, and thus
death spread to all men” (Romans 5:12).
Since it was man who brought sin
and death into God’s perfect creation,
humanity needed one of its own to
pay the perfect, infinite price to satisfy
God’s righteous wrath. But how,
all have sinned and fall short”
(Romans 3:23)? Wonder of wonders,
God became flesh! God the Son became
the perfect man, the Last Adam. He
is of our blood, yet sinless—the just,
perfect, infinite kinsman redeemer.
Dying on the Cross, Christ paid our
debt, absorbed God’s wrath due us, that
those shackled by sin in the first Adam
may repent and believe to receive salvation
through the Last Adam.
For since by man came death, by
Man also came the resurrection of the
dead. For as in Adam all die, even so in
Christ all shall be made alive. . . . And
so it is written, ‘The first man Adam
became a living being.’ The last Adam
became a life-giving spirit”
(1 Corinthians 15:21–22, 45).
Bottom line, only descendants of the first Adam can be saved by the blood of the Last Adam, Jesus Christ.
With the gospel implications grasped, it’s time to answer the question at hand.
The Bible is clear that Adam was the first man (1 Corinthians 15:45), Eve is the “mother of all living” (Genesis 3:20), and all humans are of “one blood” (Acts 17:26). The fact that all people are descendants of Adam and Eve means there is only one biological race. (It’s also the reason we’re all sinners in need of a Savior.)
So, who did Cain marry? Genesis 5:4 is the key: “After he begot Seth, the days of Adam were eight hundred years; and he had sons and daughters” (emphasis added). Jewish tradition suggests that Adam and Eve had 33 sons and 23 daughters. That means originally, close relatives like brothers and sisters married. So Cain married a sister or possibly a niece.
But wait—you can’t marry your relation, can you? Well, since there’s only one race, if you don’t marry a relative, you’re not marrying a human and you’ve really got problems! Abraham was married to his half-sister and it was not an issue. Until the time of Moses, 2,500 years after creation, God did not prohibit the marrying of close relatives (Leviticus 18:6).
But why was marrying a close relative originally okay and later forbidden by God? One reason people don’t marry close relatives today is that humans have accumulated mutations (damaged genetic information) within their DNA for thousands of years. Close relatives are likely to have mutations in common, which if passed on by both parties often result in genetic disease. If a person marries a more distant relation, they are less likely to have the same mutations, so they are less likely to pass genetic disease on to their children.
But initially this was not a problem. Adam and Eve were genetically perfect, preprogrammed straight from the hand of God. After sin and the Curse entered the world, mutations came on the scene. Originally, it was no problem to marry a close relative. Eventually, though, those mutations accumulated to a dangerous level, and that’s when God stepped in.
Remarkably, the answer is both biblically and biologically simple.
Considerably more could be said about Cain’s wife, but the question and its basic answer reveal two vital truths. First, although questions like “Where did Cain’s wife come from?” may seem benign, they are tied to the Bible’s authority as a source of truth. So they are intimately connected to the gospel. Second, when Christians stand boldly on God’s Word, they find the answers they need. Then they can consistently defend their faith and powerfully proclaim the gospel to the glory of God (1 Peter 3:15; 2 Corinthians 10:5).