The incident with Reuven and Bilhah, in light of Divrei Hayamim and the Code of Hamurabbi

Summary: The Torah's recording of the incident in Vayishlach is terse, and Chazal interpret it in two ways. And the seeming reference to the incident in Yaakov's blessing in Vaychi is cryptic. But Divrei Hayamim expands upon it. Plus, there is a fascinating parallel in the Code of Hamurabbi that sheds excellent light on the matter.

Post: In parashat Vayishlach, we read of a disturbing event:

22. And it came to pass when Israel sojourned in that land, that Reuben went and lay with Bilhah, his father's concubine, and Israel heard [of it], and so, the sons of Jacob were twelve.

כב. וַיְהִי בִּשְׁכֹּן יִשְׂרָאֵל בָּאָרֶץ הַהִוא וַיֵּלֶךְ רְאוּבֵן וַיִּשְׁכַּב אֶת בִּלְהָה פִּילֶגֶשׁ אָבִיו וַיִּשְׁמַע יִשְׂרָאֵל פ וַיִּהְיוּ בְנֵי יַעֲקֹב שְׁנֵים עָשָׂר:

Simple peshat is that Reuven actually had sexual relations with her, but Chazal are divided on the issue. Some interpret the pasuk to mean that he moved Yaakov's bed from Bilhah's tent. (And thus, as I would read it, he caused Bilhah to sleep.)

It would appear that in the blessing / prophecy Yaakov offers at the end of his life, he makes reference to this event. Thus,

3. Reuben, you are my firstborn, my strength and the first of my might. [You should have been] superior in rank and superior in power.		ג. רְאוּבֵן בְּכֹרִי אַתָּה כֹּחִי וְרֵאשִׁית אוֹנִי יֶתֶר שְׂאֵת וְיֶתֶר עָז:
4. [You have] the restlessness of water; [therefore,] you shall not have superiority, for you ascended upon your father's couch; then you profaned [Him Who] ascended upon my bed.		ד. פַּחַז כַּמַּיִם אַל תּוֹתַר כִּי עָלִיתָ מִשְׁכְּבֵי אָבִיךָ אָז חִלַּלְתָּ יְצוּעִי עָלָה:

This may be translated and interpreted in a number of ways, including that Reuven actually slept with Bilhah and that he merely moved the beds.

But, aside from this, this is Biblical poetry, and is more than a little cryptic. Pachaz Kamayim etc. does not explicitly mean what the Judaica Press translation offers above, in square brackets. Rather, it is reading ideas into the text, quite possibly correctly. My point is that it is ambiguous and so there are a number of different possible readings.

Ibn Ezra explains what it means at length (see inside), but closes with the statement
וזאת הפרשה מפורשת בדברי הימים ובחללו יצועי אביו ואמר על יהודה שהוא הנגיד והבכורה ליוסף. 
that this parasha is explained in Divrei haYamim, with ובחללו יצועי אביו, that it stated regarding Yehuda that he would be the ruler, while the birthright (though not genealogical status of firstborn) was to go to Yosef.

We see this in Divrei Hayamim I, 5:1-2:

א  וּבְנֵי רְאוּבֵן בְּכוֹר-יִשְׂרָאֵל, כִּי הוּא הַבְּכוֹר--וּבְחַלְּלוֹ יְצוּעֵי אָבִיו, נִתְּנָה בְּכֹרָתוֹ לִבְנֵי יוֹסֵף בֶּן-יִשְׂרָאֵל; וְלֹא לְהִתְיַחֵשׂ, לַבְּכֹרָה.	1 And the sons of Reuben the first-born of Israel--for he was the first-born; but, forasmuch as he defiled his father's couch, his birthright was given unto the sons of Joseph the son of Israel, yet not so that he was to be reckoned in the genealogy as first-born.
ב  כִּי יְהוּדָה גָּבַר בְּאֶחָיו, וּלְנָגִיד מִמֶּנּוּ; וְהַבְּכֹרָה, לְיוֹסֵף.  {ס}	2 For Judah prevailed above his brethren, and of him came he that is the prince; but the birthright was Joseph's-- {S}

This is a case of intra-biblical interpretation, in which one Biblical author interprets verses from elsewhere in Tanach. With the phrase  ובחללו יצועי אביו, there is clear reference to Yaakov's blessing. And he makes clear that this is a loss of certain advantages Reuven had as firstborn, which are being transferred to other brothers.

I believe that the Code of Hammurabi (learned by Yaakov in the Yeshiva Shem v'Eiver as the sayings of Rabbi Chammu) cam shed light on this. Why should the penalty for sleeping with his father's pilegesh be this loss of paternal inheritance?

See the Code of Hammurabi, law 158. People translate it in more and less expansive ways. Here are two renderings of it:

158. If a free man has sexual relations with his father's first wife, who is the mother of sons, after the death of his father, that man shall lose his paternal inheritance.

158. If any one be surprised after his father with his chief wife, who has borne children, he shall be driven out of his father's house.

As I understand it, "surprised" means caught in the act, in flagrante delicto, such that there is no room for doubt. "After his father" is all that is said, but it is understood to mean after his father's death. (Otherwise, wouldn't this merit the death penalty?) Note that this is the chief wife, rather than a second wife, a concubine, or a sexual slave. And even there, it is the chief wife who has borne children, such that she retains this status of mother of his father's children after the father's death.

Obviously, this is not 100% parallel to Reuven and Bilhah, but there are remarkable similarities, such that one could envision a local law code covering his case. Reuven was not caught with Bilhah in the act. Rather, וַיִּשְׁמַע יִשְׂרָאֵל, Yisrael heard of it. That should potentially make the penalty less. Yet it was during his father's lifetime, which should make the penalty greater. Yet, this was not with a chief-wife who had borne offspring -- it was a concubine, or a slave given by Rachel to Yaakov for the purpose of procreating. That she is a pilegesh might well lessen the offense, in this pre-Mosaic law.

The end result is that Reuven loses aspects of his inheritance, or if you will, the bechora status of his inheritance over that of his other brothers. A fitting punishment, given local laws.

We thus see that Yaakov Avinu held by the dina d'malchusa.