A particularly fascinating – and revolutionary – approach to the story of Esav's sale of the birthright to Yaakov is taken by one of the renowned 19th-century commentators.
Rav Yaakov Mecklenberg, author of "Ha-ketav Ve-ha-kabbala," claims that Esav did not sell his birthright at all (not even as a "childish game," as Rav Hirsch and Rav David Tzvi Hoffman claim). He argues that we cannot possibly ascribe to Yaakov such an insidious ploy, of capitalizing on his brother's desperate hunger to seize his birthright. Even a person who would resort to such a scheme, Rav Mecklenberg claims, would not do so as openly and unabashedly as Yaakov does. Criminals try to conceal their devious maneuvers behind a veil of legality and decency. Yaakov, however, appears to openly take advantage of his brother's hunger to grab for himself what rightfully belongs to Esav.
Rav Mecklenberg therefore advances a revolutionary approach to this narrative, which he proves based on a syntactical subtlety in the text. Immediately after telling that Esav sold his bekhora to Yaakov, the Torah writes, "And Yaakov gave to Esav bread and lentil stew… " (25:34). Rav Mecklenberg notes that the Torah here does not employ the standard past-tense form generally used in Biblical narrative, which in this case would yield, "Va-yiten Yaakov le-Esav… " Instead, the Torah describes the action by first mentioning the subject, followed the predicate: "Ve-Yaakov natan le-Esav." This form generally indicates that the event described occurred prior to this point in the narrative. (The most famous example, perhaps, is the verse in Parashat Bereishit – "Ve-ha-adam yada et Chava ishto"; see Rashi to Bereishit 4:1.) Accordingly, we should translate this verse as, "Yaakov had given to Esav bread and lentil stew." Meaning, even before Esav "sold" the birthright to Yaakov, Yaakov fed Esav. We must conclude, therefore, that Yaakov gave Esav food even before the entire discussion concerning the sale of the birthright.
How, then, are we to read this narrative?
Rav Mecklenberg explains that immediately upon hearing Esav's request for food, Yaakov fed him without delay. How else should we expect a decent person with a full pot of food to react to his brother's hunger? Over the course of the meal, the conversation somehow moved onto the topic of the birthright. (According to the Midrash claiming that Avraham died that day, we can easily understand why Esav and Yaakov would begin discussing the issue of succession and what will occur with their father passes on.) At this point, Esav expressed his disinterest in the bekhora and belittled its importance. Yaakov then remarked, "Mikhra kha-yom et bekhoratekha li" (25:31). All commentators translate this phrase in the imperative form: "Sell to me as on this day your birthright." Rav Mecklenberg, however, argues that the imperative form of the verb "m.kh.r." is "mokhra" (with a "kamatz chazak" underneath the letter "mem"), rather than "mikhra." He therefore suggests that the word "mikhra" is equivalent to the Hebrew word "mekhura" – "it is sold."
Yaakov here tells his brother that his indifference to the birthright renders it automatically transferred to his brother (Yaakov). If Esav has no interest in the privileges of the bekhora, then he ipso facto relinquishes all rights to this status and it is thus conferred upon Yaakov. And when the Torah writes, "va-yimkor et bekhorato le-Yaakov" (25:33), which we generally translate as, "he sold his birthright to Yaakov," it in fact means that Esav relinquished his claim to the bekhora, such that it naturally went to Yaakov. What transpired here was thus not an actual sale, but rather an agreement between the two brothers (over the dinner table) that the bekhora has been automatically transferred to Yaakov.
Clearly, however, Rav Mecklenberg represents a lone voice in this regard, and, as he himself acknowledges in his commentary, all other commentators understood the verses to mean that Yaakov demanded the birthright in exchange for the food he fed to his brother.