To shed some light on this matter, we will introduce a fundamental concept gleaned from the incredible teachings of the great Rabbi Tzadok HaKohen, zy”a, in Pri Tzaddik (Vayigash 3). These two kingly figures, Yehudah and Yosef, represent two distinct paths in the service of Hashem—the path of the ba’al teshuvah and the path of the tzaddik. Yosef, who withstood the trying ordeal with his master’s wife in Mitzrayim—related to kedushah and morality—represents the consummate tzaddik, who is able to withstand and defeat his yetzer hara. As such, he is the paradigm of the midah "צדיק יסוד עולם".
Yehudah, on the other hand, admitted publicly to his misconduct in the matter of Tamar, as it is written (Bereishis 38, 26): "ויכר יהודה ויאמר צדקה ממני"—Yehudah recognized them and he said, “She is right!” Thus, he represents the ba’al teshuvah. In this merit, he deserved to become the King of Yisrael, as we are taught in the Midrash (B.R. 99, 7). Regarding the berachah Yaakov Avinu bestowed upon Yehudah (ibid. 49, 8), they expounded: HKB”H said to him (to Yehudah): "יהודה אתה יודוך אחיך"—Yehudah, you your brothers shall acknowledge. You acknowledged your culpability regarding Tamar, so shall your brothers acknowledge you as their king.
Now, it states in Sefer Yetzirah (6, 2): "לב בנפש כמלך במלחמה"—the heart in the soul is like a king in battle. Accordingly, the king is the heart of the people. In a similar vein, the Rambam writes about the King of Yisrael (Hilchos Melachim 3, 6): When the Torah forbade the king from accumulating many wives, its emphasis was that his heart not go astray, as it warns (Devarim 17, 17): “Lest his heart go astray.” His heart is the heart of the entire congregation of Yisrael. The heart is a human being’s source of life; it provides blood flow to the entire body. Similarly, the king is the heart of the entire people of Yisrael; his actions affect all of Yisrael.
Furthermore, we know that the heart consists of two distinct cavities. The yetzer tov resides in the right cavity, while the yetzer hara resides in the left cavity. This is taught in the Midrash (Bamidbar Rabbah 22, 8) in relation to the passuk (Koheles 10, 2): “The heart of a wise man is to his right; while the heart of a fool is to his left.” “The heart of a wise man is to his right” refers to the yetzer tov, which has been placed on his right side, while “the heart of a fool is on his left,” refers to the yetzer hara, which has been placed on his left.
Based on this understanding, Rabbi Tzadok asserts that Yehudah and Yosef, the two kings, represent the two cavities of the heart. Yosef, the epitome of a tzaddik, represents the right cavity of the heart, where the yetzer tov resides. As such, he overcame the yetzer hara in the left cavity, in keeping with the dictum (Avos 4, 1): "איזהו גבור הכובש את יצרו"—who is a mighty hero? He who conquers his yetzer. In contrast, Yehudah represents the left cavity of the heart, where the yetzer hara resides. This explains why it was orchestrated from above to appear as if he was defeated by the yetzer hara in the matter of Tamar. Thus, he paved the way for all ba’alei teshuvah to rest assured that it is possible to make amends for all sins by means of teshuvah.
Yosef and Yehudah Represent the Two Mashiachs
Continuing this line of reasoning, Rabbi Tzadok develops this fascinating idea further. This explains very nicely why David HaMelech resulted from the union of Yehudah and Tamar. Just like Yehudah, it was announced from the heavens that it was his holy mission to pave a path for ba’alei teshuvah. As we have learned in the Gemara (A.Z. 4b): "לא דוד ראוי לאותו מעשה דכתיב (תהלים קט-כב) ולבי חלל בקרבי... אלא לומר לך שאם חטא יחיד אומרים לו כלך אצל יחיד... והיינו דרבי שמואל בר נחמני אמר רבי יונתן, מאי דכתיב (שמואל ב כג-א) נאום דוד בן ישי ונאום הגבר הוקם על, נאם דוד בן ישי שהקים עולה של תשובה". Left to his own devices, David HaMelech would not have performed that deed. It was ordained from above that David would fail in the matter involving bas Sheva. As a result, he established the pathway of teshuvah — repentance—for all of Yisrael to emulate. Thus, he provided Yisrael with a form of atonement and tikun.
Let us elaborate. In the words of the Rambam, as the King of Yisrael: His heart is the heart of the entire congregation of Israel. Hence, David HaMelech had to follow in the footsteps of Yehudah, the head of his shevet, who is also depicted as a king. It was orchestrated from Heaven that both would fail in an incident that appeared to be a sin in order to demonstrate the path of teshuvah for all of Yisrael.
Rabbi Tzadok goes on to explain that, as taught in the Gemara (Succah 52b), HKB”H is destined to send two Mashiachs to redeem Yisrael—a descendant of Yosef, Mashiach ben Yosef, and a descendant of Yehudah, Mashiach ben David. The former will inculcate kedushah, so that the people of Yisrael will emulate the ways of a tzaddik. In contrast, the latter will inspire Yisrael to rectify all of their transgressions by means of teshuvah. In the merit of both of them, HKB”H will bring about the geulah for Yisrael.
