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 And in the forty-fifth jubilee, in the second week, (and) in the second year, [2165 A.M.] Judah took for his first-born Er, a wife from the daughters of Aram, named Tamar. 2 But he hated, and did not lie with her, because his mother was of the daughters of Canaan, and he wished to take him a wife of the kinsfolk of his mother, but Judah, his father, would not permit him. 3 And this Er, the first-born of Judah, was wicked, and the Lord slew him. 4 And Judah said unto Onan, his brother 'Go in unto thy brother's wife and perform the duty of a husband's brother unto her, and raise up seed unto thy brother.' 5 And Onan knew that the seed would not be his, (but) his brother's only, and he went into the house of his brother's wife, and spilt the seed on the ground, and he was wicked in the eyes of the Lord, and He slew 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. Teir 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). Tis 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) afer 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