Sometimes stories in the Bible seem strange to us—both in terms of content and in terms of why they are included. The second set of twins in Genesis seems to fit that description.
Genesis 38:27-30 explains that Tamar gave birth to twin sons for Judah. One, Zerah, extended one hand from the womb, but then pulled it back; his brother, Perez, came out first. Because Perez came out first, despite Zerah apparently having started to be born first, the former was named “Perez.” His name means “breaking out,” because he had broken through ahead of his brother.
Such a birth was highly unusual (although one need only read the ancient gynecological work of Soranus to discover a range of differing positions in which babies were reported to sometimes come out). In such circumstances, people might view the unusual yet safe birth as portending Perez’s future greatness.
Nevertheless, Genesis—and the rest of the Pentateuch—never again mentions Perez except in genealogies mentioning his descendants. Why does Genesis “waste” space narrating this unusual birth instead of elaborating more on other characters that the narrative develops more fully?
Although Perez does not appear again in any significant way in Genesis, twins do. Earlier in Genesis (Genesis 25:24-26), Perez’s grandfather Jacob had emerged right after Esau, clutching Esau’s heel—another very unusual birth. Jacob ultimately surpassed Esau, receiving his birthright and his blessing (two similar-sounding Hebrew words that together offer a nice play on words). Thus when Genesis’s first hearers came to the story of Perez’s birth, they would remember the birth of Jacob who also ultimately bested his twin brother (although a bit later in life).
Genesis thus seems to hint at a future significance for Perez. What might that be? When Jacob blesses his children, he promises rulership to the descendants of Judah (Genesis 49:10), even though the preceding narratives might have expected that promise to go to one of the sons of Joseph instead (Joseph does get the double portion that normally went to the firstborn). Centuries later, however, descendants of Judah’s son Perez celebrated his special birth and prayed for Ruth’s descendants to be like Tamar’s descendants through Perez (Ruth 4:12). The grandson of Ruth’s son Obed was King David (Ruth 3:21-22), and Perez turned out to be part of the royal line of Jesus (Matthew 1:3; on this, see also Jesus’s genealogy; Jesus’s genealogy in Matthew).
Sometimes we see God working in what appear to be relatively personal matters, but these may prove even more consequential in his sight. God has a plan that stands through history, and he is worthy of our trust.