Or HaChaim on Deuteronomy 33:7/אור החיים על דברים ל״ג:ז׳

1 שמע ה׳ קול יהודה, "Hearken, O Lord, to the voice of Yehudah." Seeing that Yehudah had sinned in his relationship with Tamar and had confessed his guilt (Genesis 38,26) when he said: "she is more righteous than I," Moses prayed that G'd should accept his confession. He mentioned this only in order to be able to continue with ואל עמו תביאנו. We have explained in our commentary on Genesis 49,9 (page 424) how the union of Yehudah and Tamar enabled Yehudah to qualify for the description אריה, a fully grown lion. Yehudah's spiritual ascent had been due to his being able to tear himself away from the prey, i.e. from the pools of souls that had been taken captive by the forces of Satan as a result of Adam's sin. In our verse Moses alludes to this when he refers to Yehudah's "hands having performed a mighty deed."

2ועזר מצריו תהיה, "may she be a helper against his enemies." the word תהיה, refers to the eventual descendant of Yehudah, Ruth the Moabite, without whom even such illustrious people as Zerach and Peretz could not have guaranteed that he would become the founder of the dynasty culminating in King David and eventually the Messiah. The word עזר, is an allusion to the first female, Eve, who was described by the Torah (Genesis 2,18) as Adam's helper, עזר. Similarly, Yehudah's female descendant Ruth would perform this role in asssuring that he could attain his destiny. Compare also what I have written on Genesis 43,9 (page 347).