Genesis 38:30

And afterward came out his brother, that had the scarlet thread upon his hand: and his name was called Zarah.

The verse records the birth of Zarah, who came out after his brother with the scarlet thread upon his hand, as one of the twin sons born to Tamar and Judah and marked at birth by the thread. It belongs to the account in Genesis 38 of the sin and wrongdoing of Judah and his family. In narrative order, the chapter comes after Joseph was sold into Egypt and before the account of Joseph being bought by Potiphar in Egypt. The verse stands within Genesis 37-41, which records Joseph's early life, the envy of his brothers, his sale to the Ishmaelites as a slave, his sojourn in Egypt, and God's wondrously good dealings with him in it all. The chapter is included among the accounts showing the sad fruits of Jacob's mistakes, including low standards of morality and crime.

The record of wrongdoing is given to expose sin so that readers may shun it, not to indulge lust or to excuse sin. The chapter also points to God's remedy through his love, mercy, and power. Pharez, the twin brother in the chapter, was born of a harlot and became an ancestor of Christ, illustrating the degraded human line from which Christ sprang according to the flesh. Zarah's place in Tamar's family history makes him part of the ancestry of Christ. That ancestry, with Jacob's selfish craft, David's passions, Rahab's heathen background, and the sins of Solomon and the kings of Judah, tended to concentrate all the weaknesses of humanity in Christ.

Although his mother was pure and godly, Christ's human nature was therefore more subject to the infirmities of the flesh and to sinful tendencies than if he had been born before the race deteriorated physically and morally. This proves Christ took the flesh not of sinless man but of sinful fallen man, since only sin causes death, and it was not accidental but necessary for redemption that he be made like his brethren to suffer death and temptation. The lineage includes women with shameful or socially disfavored histories and therefore presents hope to the fallen, even to those who inherit strong sinful tendencies.