Genesis 38:13-14

"And it was told Tamar, saying, Behold, thy father-in-law goeth up to Timnah to shear his sheep. And she put off from her the garments of her widowhood, and covered herself with her veil, and wrapped herself, and sat in the gate of Enaim, which is by the way of Timnah; for she saw that Shelah was grown up, and she was not given unto him to wife."

Thus, Tamar was keeping abreast of all developments. She could see the transparent fraud Judah was practicing against her, and she doubtless had also become aware of Judah's immoral habits. Whatever stories got around about Judah, Tamar remembered. Therefore, she took matters into her own hands, stripped off the garments of her widowhood, clothed herself in the garb of one of the sacred prostitutes seen everywhere in Canaan, and placed herself in a likely place to attract the attention of Judah. Sheep-shearings were usually fiesta occasions, and Tamar accurately understood the things that usually went on at such celebrations.

"Covered herself with her veil, and wrapped herself..." Those who accept the medieval superstition that even found its way into the KJV and ASV versions of the Bible, that the wearing of a veil by women was in some manner a mark of virtue and chastity, should take a look at this. It had the very opposite meaning. "According to Assyrian law, only a cult prostitute was to wear a veil."[25] Evidently, Judah did not know this; and thus he mistook Tamar for a common prostitute (Genesis 38:15), but when he sent Hirah to redeem his pledge (Hirah having in all probability inquired of Judah as to how the woman was dressed), Hirah, pagan that he was, promptly recognized by the attire what he assumed to be one of the cult priestesses, using the technical word for sacred, or temple prostitute repeatedly in Genesis 38:21 and Genesis 38:22. This very evil was the backbone of pagan worship in Canaan.