How the Promise of a Future Redeemer Helps Make Sense of the Sins of Er and Onan, the Strangest Story in the Bible

I’d be afraid if any children’s Sunday school class had ever taught the story of Er and Onan in Genesis 38. I’d be surprised if a pastor had ever devoted an entire sermon to that particular chapter. Even preachers who methodically work through every chapter of the Bible may just make passing mention about this strange Bible story. And I believe this happens because they don’t understand the significance of what these narratives reveal. They don’t truly understand the context.

The chapter begins with a genealogy, but as we know by now, the record of a person’s ancestry was vitally important to the ancient Israelites because with every new son, the nation would ask themselves, “Might this be the promised Messiah?” If you’re familiar with Jesus’s lineage, you should see some familiar names in this passage:

And it came to pass at that time, that Judah went down from his brethren, and turned in to a certain Adullamite, whose name was Hirah.And Judah saw there a daughter of a certain Canaanite, whose name was Shuah; and he took her, and went in unto her.And she conceived, and bare a son; and he called his name Er.And she conceived again, and bare a son; and she called his name Onan.And she yet again conceived, and bare a son; and called his name Shelah: and he was at Chezib, when she bare him.And Judah took a wife for Er his firstborn, whose name was Tamar.And Er, Judah's firstborn, was wicked in the sight of the Lord; and the Lord slew him.And Judah said unto Onan, Go in unto thy brother's wife, and marry her, and raise up seed to thy brother.And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother's wife, that he spilled it on the ground, lest that he should give seed to his brother.And the thing which he did displeased the Lord: wherefore he slew him also (Genesis 38:1–10).

This story is so strange and explicit that it couldn’t even be filmable if the entire Bible were to be made into a movie. But now that you understand the extreme importance of producing an heir, the context of the story provides insight into its apparent strangeness. The Lord “slew” Onan because Onan abdicated his responsibility to produce an heir who could have very well been the promised Messiah.

The Strange History of Jesus's Lineage

In fact, the story of the direct lineage of Judah becomes even stranger. In time, Judah unknowingly sleeps with his daughter-in-law, Tamar, thinking that she’s a prostitute. Tamar becomes pregnant and then gives birth to Phares. Matthew 1, which recounts the genealogy of Jesus, verifies this sordid story: “And Judas begat Phares and Zara of Thamar” (Matthew 1:3a). “Judas” is Judah; “Thamar” is Tamar.

Without the promise of Genesis 3:15, the story of how Judah was ever in Jesus’s lineage fails to make much sense. But because we know how important the seed leading to the one who would crush the serpent’s head was to every ancient Israelite, we have a much better understanding as to why such a strange story was included in the Bible.

At the end of days, the Apostle John reports that an angel asks, “Who is worthy to open the book, and to loose the seals thereof?” (Revelation 5:2). That angel is speaking about a locked scroll that, I believe, ultimately signifies Satan’s crushing. The one who can open that book will be the only one with the power to crush Satan’s head.

Once he’s heard the question, John bemoans his fate: “And no man in heaven, nor in earth, neither under the earth, was able to open the book, neither to look thereon. And I wept much, because no man was found worthy to open and to read the book, neither to look thereon” (Revelation 5:3–4).

The Central Question of the Old Testament

In many ways, the plot line of the Old Testament is a long answer to the question, “Who is worthy?” Is Adam worthy? Is Cain or Abel? Is Seth? Is Noah or Abraham or Joshua or Gideon or Samson or David worthy? And time and time again, the answer proves to be "no."

This is not the promised one. Sorry. Try again.

But finally a man is born who is the promised Messiah.

A man is born who will right the wrongs we’ve created.

A man is born whose heel will be crushed but who will crush the Enemy’s head once and for all.

John is reminded of that fact: “And one of the elders saith unto me, Weep not: behold, the Lion of the tribe of Judah, the Root of David, hath prevailed to open the book, and to loose the seven seals thereof. And I beheld, and, lo, in the midst of the throne and of the four beasts, and in the midst of the elders, stood a Lamb as it had been slain . . . ” (Revelation 5:5–6).

The one who is worthy is the One who has been slain yet has prevailed. He alone finally fulfills the promise of Genesis 3:15.