Genesis 38:17

It would be normal for Tamar to ask for a pledge if the man did not have the money to pay. A woman in such a position would not trust anyone to send the money.

Tamar understood she needed to act to secure her family's future. Following the levirate custom (see study note on 38:8), she remained loyal to her dead husband. She had a legal right to have a child with Judah's son or Judah himself. So she tricked her father-in-law into having sexual relations with her. Again, Jacob’s family experiences deception, this time by a Canaanite daughter-in-law.

The story of Judah and Tamar is a carefully placed break in the larger story. It shows what was happening in Judah’s family. Judah would later become an important leader. The story also shows the early stages of the family mixing with the people of the land. This helps explain why God sent the family to Egypt (chapters 39–47).

The Egyptians kept themselves separate from other peoples (43:32). Because of that, the Israelites were more likely to keep their own identity in Egypt than in Canaan.