Genesis

And she put her widow’s garments off from her, and covered her with a vail, and wrapped herself, and sat in an open place, which is by the way to Timnath; for she saw that Shelah was grown, and she was not given unto him to wife.

And Joab sent to Tekoah, and fetched thence a wise woman, and said unto her, I pray thee, feign thyself to be a mourner, and put on now mourning apparel, and anoint not thyself with oil, but be as a woman that had a long time mourned for the dead:

And the king said unto her, What aileth thee? And she answered, I am indeed a widow woman, and mine husband is dead.

Thou shalt not uncover the nakedness of thy daughter in law: she is thy son’s wife; thou shalt not uncover her nakedness.