Charles Ellicott Commentary Matthew 1:3

"and Judah begat Perez and Zerah of Tamar; and Perez begat Hezron; and Hezron begat Ram;" — Matthew 1:3 (ASV)

Tamar — The inclusion of women's names in genealogies was the exception rather than the rule among the Jews. However, there are enough instances in the Old Testament (for example, Keturah, Genesis 25:1; the wives of Esau, Genesis 36:10; Timnah, Genesis 36:22; Mehetabel, Genesis 36:39; Azubah, the wife of Caleb, 1 Chronicles 2:18; Achsah, his daughter, 1 Chronicles 2:49; and many others) to make their inclusion here seem quite natural, even without assuming a specific purpose. It was enough that the women were historically notable.

In Tamar’s case, there were enough precedents for such an honorable mention. In the time of Ruth, she was as much the heroine of the tribe of Judah as Rachel and Leah were of all Israel, and her name was included in the formula of nuptial blessing (Ruth 4:12). Her name also appears in the genealogies of 1 Chronicles 2:4. It appears from the language of the Talmud that the Jews viewed her strange history—which is revolting to us—with very different feelings. To them, she was someone who, at the risk of shame and possibly even death, had preserved the line of Judah from destruction, and was therefore “considered worthy to be the mother of kings and prophets.” The mention of Zerah, though not in the line of succession, follows the precedent of 1 Chronicles 2:47.