Moses
Genesis 38:13ESV·traditional attribution

And when Tamar was told, “Your father-in-law is going up to Timnah to shear his sheep,”

John Calvin Reformed @genevareformer

13. And it was told Tamar. Moses relates how Tamer avenged herself for the injury done her. She did not at first perceive the fraud, but discovered it after a long course of time. When Shelah had grown up, finding herself deceived, she turned her thoughts to revenge. And it is not to be doubted that she had long meditated, and, as it were, hatched this design.

Matthew Henry Presbyterian @wholebiblehenry

It is a very ill-favoured story that is here told concerning Judah; one would not have expected such folly in Israel. Judah had buried his wife; and widowers have need to stand upon their guard with the utmost caution and resolution against all fleshly lusts. He was unjust to his daughter-in-law, either through negligence or design, in not giving her his surviving son, and this exposed her to temptation. I.

Commenting on Genesis 38:12-23

John Gill Reformed Baptist @doctorgill

And she put her widow's garments off from her,.... By which it appears that in those times and countries it was usual for widows to have a different apparel from others, especially in the time of their mourning, as it has been since in other nations, and with us at this day, and which is commonly called "the widow's weed": and covered herself with a...