Faithfulness

But God came to Abimelech in a dream of the night, and said to him, “Behold, you are a dead man because of the woman whom you have taken, for she is married.
Genesis 20:3 (NASB)

The rabbis suggest that the people of Abraham’s day believed that faithfulness is of such great importance that adultery was considered worse than murder.

Back in Genesis 12, Abram’s fear was that the men of Egypt would be willing to MURDER him, but he’s not worried that they’ll simply abduct Sarai and sleep with her or take her as their own wife.

It came about, when he was approaching Egypt, that he said to his wife Sarai, “See now, I know that you are a beautiful woman; and when the Egyptians see you, they will say, ‘This is his wife’; and they will kill me, but they will let you live.
Genesis 12:11-12 (NASB)

Perhaps part of this idea comes from seeing that God commanded faithfulness first in Genesis 2:24, but the story of murder isn’t shown until Genesis 4 when Cain kills Abel.

And perhaps this is why God warns Abimelech the way He does.

Abel’s Wife

Perhaps Abel was married.

Consider the law of the Kinsman Redeemer:

If brothers dwell together, and one of them dies and has no son, the widow of the dead man shall not be married to a stranger outside the family; her husband’s brother shall go in to her, take her as his wife, and perform the duty of a husband’s brother to her. And it shall be that the firstborn son which she bears will succeed to the name of his dead brother, that his name may not be blotted out of Israel.
Deuteronomy 25:5-6

This law defines how to be a “brother’s keeper.” Perhaps we’re told that Cain left and knew his wife (Genesis 4:16-17) specifically because he wouldn’t marry Abel’s wife in order to continue his dead brother’s name.

Neither Cain nor Abel

We always call it the story of “Cain & Abel,” but this ignores a critical part of the story.

Eve assumes God will use Cain – she says as much when she first speaks. And we, seeing Abel’s sacrifice, assume God will use the younger son to fulfill the blessing of “be fruitful and multiply.” But our assumptions are dashed by murder. Cain leaves the scene, and Abel dies. What will God do to solve this problem?

Perhaps the right name of the story should be “Not Cain, not Abel, but through Seth.”

Seth’s name means “appointed.” As in, selected by God to be used for a specific purpose. God’s purpose.

This is the nature of things.