Shofetim 11:39-40

Orthodox Jewish Bible

³⁹ And it came to pass at the end of two chodashim, that she returned unto her av, who did with her according to his neder which he had vowed; and she knew no man. And it was a chok in Yisroel,

⁴⁰ That the banot Yisroel went yearly to lament the bat Yiftach the Gileadi arba’at yamim bashanah.