Final answer:
Tamar, when realizing that Judah would not honor the obligation of levirate marriage with his third son, took matters into her own hands to ensure her rights and lineage by conceiving children with Judah himself.
Step-by-step explanation:
When she realized that Judah would not let his third son marry her, Tamar took bold action to secure her future and assert her rights. The narrative reflects a tension between the obligations and rights within family structures and societal expectations of the time.
Faced with childlessness and the refusal of Judah to fulfill his family obligation, Tamar disguised herself and ensured her lineage by conceiving children with Judah himself. Her story raises themes of agency and justice, as seen in her assertive steps to rectify a situation where societal norms and individual promises were not honored.