I commented on Gratitude:

What does “todah” mean? As it stands, it means “thanks”. The same root conjugated as “vidui” means to “confess”. Last, when the mishnah wants to stress that something is outside of a dispute, “hakol modim” — “all agree”. What do thanks, confession and agreement have in common?

When I thank someone, I acknowledge his actions had an impact on me. When I confess, I am admitting that my actions had an impact on him. And when we are modim, we realize that an idea isn’t mine or yours, but ours. The point in common in the three uses of the root is a realization of connectedness.

Yehudah was named for hoda’ah with more of a connotation of gratitude:

תַּהַר עוֹד וַתֵּלֶד בֵּן, וַתֹּאמֶר “הַפַּעַם אוֹדֶה אֶת ה׳”; עַל כֵּן קָרְאָה שְׁמוֹ “יְהוּדָה”; וַתַּעֲמֹד מִלֶּדֶת.

And [Leah] became pregnant again, and said “This time I will thank [odeh] Hashem”; therefore she called his name “Yehudah”; and she finished birthing children.

–Bereishis 29:35

And yet, Yehudah may be most noted for his readiness to do teshuvah and confess his mistakes — the vidui sense of the root for which he was named. Tamar held out his signet ring, cords and staff, and identified Yehudah to himself as the one who had gotten her pregnant, while still keeping his guilt a secret from others. Yehudah, however, confesses his guilt — and her innocence — in public.

וַיַּכֵּר יְהוּדָה, וַיֹּאמֶר “צָדְקָה מִמֶּנִּי! כִּי עַל כֵּן לֹא נְתַתִּיהָ לְשֵׁלָה בְנִי, וְלֹא יָסַף עוֹד לְדַעְתָּה.”

And Yehudah recognized them and said, “She is more righteous than me! Because I didn’t give her to Sheilah my son, and I did not allow anyone else to know here.”

–Bereishis 38:26

The gemara [Makkos 11b] merits this example as teaching Reuvein the art of confession. A merit that Moshe hints at in his blessing in veZos haBerakhah (33:6-7), ” יְחִי רְאוּבֵן וְאַל יָמֹת, וִיהִי מְתָיו מִסְפָּר. וְזֹאת לִיהוּדָה…. — Let Re’uvein live and not perish, that his number not become few. And this is for Yehudah…” Phrasing the opening of Yehudah’s blessing so that it can also be heard as referring back — “and this” Re’uvein’s blessing “is for Yehudah…”

Yehudah’s path in Torah observance, for which his tribe is named, the Kingdom of Judea (Malkhus Yehudah) was named, and for which we today are called “Jews” is as much about the centrality of gratitude as the importance of confession

The story of Yehudah and Tamar (ch. 38) is adjacent to that of Yosef’s servitude in Potiphar’s home, and his resisting Potiphar’s wife’s attempt to seduce him (ch. 39). This placement invites us to compare and/or contrast the two stories. Yehudah succumbs to temptation, but confesses and repents, becomes an exemplar of a ba’al teshuvah. Yosef is tested and stands up to the challenge, and the Zohar states (1:194b) it is for this that Chazal call him “Yosef haTzadiq“.

Both rise to royalty. Yosef, in the house of Par’oh, and in his eventual descendent, the mashiach beis Yoseif who is destined to lead the war against Gog uMagog, and fall in battle. But it is Yehudah from whom the Jewish People’s true royal house descends, and from whom the mashiach who brings world peace will be born. Perhaps it is an example of Rav Avahu’s famous words (Berakhos 34b):

דאמר רבי אבהו: מקום שבעלי תשובה עומדין – צדיקים גמורים אינם עומדין, שנאמר: (ישעיהו נז:יט) “שָׁלוֹם שָׁלוֹם לָרָחוֹק וְלַקָּרוֹב” — “לָרָחוֹק” ברישא, והדר “לַקָּרוֹב”.

… As Rabi Avahu said, “In the place where baalei teshuvah stand — the fully righteous cannot stand. As it says “Peace, peace, to those who are afar, and those who are near.” (Yeshaiah 57:19). “To those who are afar” — initially, and after, “to those who are near.”

Yehudah’s progeny are not only given a position Yosef’s family is not as suited to fill, but it is the matter of war vs peace that distinguishes the two mashiachs — as per the pasuq Rav Avahu quotes — “Peace, peace, to those who start out afar, and come near!”