Judges 11:37-39

New International Version

³⁷ But grant me this one request,” she said. “Give me two months to roam the hills and weep with my friends, because I will never marry.”

³⁸ “You may go,” he said. And he let her go for two months. She and her friends went into the hills and wept because she would never marry. ³⁹ After the two months, she returned to her father, and he did to her as he had vowed. And she was a virgin.

From this comes the Israelite tradition