Genesis 38:1
2 There Judah saw the daughter of a Canaanite man named Shua. Judah acquired her as a wife and slept with her. 3 She became pregnant and had a son. Judah named him Er. 4 She became pregnant again and had another son, whom she named Onan. 5 Then she had yet another son, whom she named Shelah. She gave birth to him in Kezib. 6 Judah acquired a wife for Er his firstborn; her name was Tamar. 7 But Er, Judah’s firstborn, was evil in the Lord’s sight, so the Lord killed him. 8 Then Judah said to Onan, “Sleep with your brother’s wife and fulfill the duty of a brother-in-law to her so that you may raise up a descendant for your brother.”
Jubilees 41:2
1 In the forty-fifth jubilee, the second week during the second year [2165], Judah took as a wife for his first-born Er one of the Aramean women whose name was Tamar. 2 He hated her and did not lie with her because his mother was a Canaanite woman and he wanted to marry someone from his mother’s tribe. But his father Judah did not allow him. 3 That Er, Judah’s first-born, was evil, and the Lord killed him. 4 Then Judah said to his brother Onan: ‘Go in to your brother’s wife, perform the levirate duty for her, and produce descendants for your brother.’ 5 Onan knew that the descendants would not be his but his brother’s, so he entered the house of his brother’s wife and poured out the semen on the ground. In the Lord’s estimation, it was an evil act, and he killed him.
Notes and References
"... Genesis 38 recounts how Judah ended up sleeping with his daughter-in-law, Tamar. When Jubilees retells this story, it provides both Judah and Tamar with a legal exculpation that the biblical story did not mention. It asserts that Tamar’s earlier marriages to Er and Onan had never been consummated (see Jubilees 41:2-5, 27-28). As a result, she was still a virgin when the incident with Judah occurred—and thus legally available to be married to him. Their union was therefore altogether licit and neither of them was liable for punishment (as indeed they were not punished in the biblical narrative). Yet in the middle of the Jubilees narrative comes a passage summarizing the legal lesson to be learned from it (41:23-26). This passage—characterized by the typical “terminology of the Heavenly Tablets”—mentions nothing about Tamar still being a virgin nor, consequently, anything about the innocence of the two participants. Instead, as far as the author of this passage was concerned, Judah was fully deserving of punishment and only “had forgiveness because he turned away from his sin” (41:25) after pleading and lamenting (41:24) before God. (It says nothing about the guilt or innocence of Tamar.) But if, according to the surrounding narrative, Judah did nothing wrong, why should he have had to plead and lament? ..."
Kugel, James L. A Walk through Jubilees: Studies in the Book of Jubilees and the World of Its Creation (p. 228) Brill, 2012