Judah, Er’s father, was the fourth of six sons Leah gave birth to with Jacob. At the beginning of Genesis, chapter thirty-eight, he meets or reconnects with an Adullamite friend named Hirah. Defying this directive, Judah takes a Canaanite woman, the daughter of a man named Shua, presumably as his wife. Then he takes a wife for his firstborn Er, Tamar. After meeting up with Hirah, Judah made two suspect decisions against God’s law.
Judah did not righteously go about his life the way God intended but randomly went to a Canaanitish woman to make a family. The decision to mix with the Canaanites affected the entire family line. Er was slew by God for his wickedness. Onan, the second-born, did not fulfill his obligation to have children with Tamar. However, instead, Onan takes advantage of both the situation and Tamar. He uses her for sex but interrupts the act at the very end to prevent conception. The encounter is not a single event but a pattern: it was Onan’s choice “whenever” he had sex with Tamar. For that, God will strike Onan dead.
Judah’s actions and scandalous decision-making continues to hurt him and his family. He deceives Er’s wife Tamar into thinking he will have Shelah be her husband and have children once he becomes of age. After verbally telling his daughter-in-law, Judah did not follow through on his promise. Then in the process of time, Judah’s wife dies, and he plans to travel somewhere in Timnath. Tamar disguises herself as a harlot from a widow to deceive Judah. He falls for it and sleeps with her, only to discover that he had an intimate encounter with his daughter-in-law. Judah ends up getting Tamar pregnant. What goes around comes around. Judah reaps what he had sown. His odd decision-making catches up with him.