In Rav Bin Nun’s reading, the ברית בין הבתרים isn’t really a covenant in the sense of an agreement between parties. It is a promise from ה׳ about the role that Avraham’s descendants will have in history. That is why Avraham sleeps through the entire experience. Those descendants have no responsibilities in this covenant. That’s what he means when he says that ברית בין הבתרים is היסטורי-לאומי, and that it won’t apply for generations. Israel’s moment on the stage of history lies far in the future.
ברית מילה introduces the concept of מצווה, of commandedness. Avraham is awake, and has responsibilities. He has to two things: the act of מילה itself, and transmitting that מצווה to his descendants. In return, he will be given ארץ כנען, but (Rav Bin Nun says) not as a matter of conquest and sovereignty but as a place to live and fulfill those commandments. He says that is what אחזת עולם means, in ברית מילה. In ברית בין הבתרים, the term is לרשתה, which implies removing those who lived there before.
Rav Bin Nun notes the distinction between “הארץ” in ברית בין הבתרים and “ארץ כנען” in ברית מילה. ארץ כנען is a place; it has defined borders. הארץ is much more vague; it is wherever the influence of בני ישראל is dominant.
So there is some responsibility in the ברית בין הבתרים model: to be human beings, to be (literally) a mensch. But it’s not a מצווה per se.
To summarize: ברית בין הבתרים is ה׳'s promise that Avraham’s descendants, בני ישראל, would be His representatives on Earth. ברית מילה is the “deal”: Avraham’s descendants keep the מצוות, and they get to live in the land of Israel, the place where the מצוות are to be done.
Rav Soloveitchik makes a similar distinction in ה׳'s relationship with בני ישראל when the ברית is finally fulfilled. In קול דודי דופק, he distinguishes between ברית יציאת מצרים and ברית סיני. He calls the first ברית גורל, the covenant of fate, and the second ברית יעוד, the convenant of destiny.
At יציאת מצרים, the people stayed inside and were passive in the face of ה׳'s miracles against the Egyptians. At הר סיני, they had to explicitly say נעשה ונשמע, to accept the commandments and their part in the ברית.
The ברית גורל of יציאת מצרים was the fulfillment of the ברית בין הבתרים. It was the direct intervention of G-d in history: היחיד כפוף ומשועבד בעל כרחו למציאות הלאומית-הגורלית. The ברית ייעוד of מעמד הר סיני was the renewal of ברית המילה for the people as a whole: מדעת שהאומה בחרה בו ברצונה החפשי.
Our relationship with הקב״ה is a dialectic of the two בריתות of Avraham. And when we look at the text of our parsha, we see that they use two different names of G-d. The ברית בין הבתרים uses שם הויה throughout. The ברית המילה starts with שם הויה, then switches to שם אלוקים throughout. We discussed the difference last week:
But is ברית בין הבתרים, with גר יהיה זרעך בארץ לא להם ועבדום וענו אתם ארבע מאות שנה, really a manifestation of רחמים? The דין/רחמים distinction doesn’t seem to correspond to the differences here. I think the answer goes back to what Rabbi Shulman said last week. מִדַּת רַחֲמִים and מִדַּת הַדִּין are really much bigger than G-d’s mercy or harsh judgement. The difference is between immanence and transcendence. שם אלוקים represents the Transcendent G-d, beyond human understanding and recognition. שם הויה represents the Immanent G-d, Whose hand we see in our lives and in history.
The truth is that both בריתות start with שם הויה. The very nature of ברית implies a personal connection between us and הקב״ה. But we don’t always feel that. The sense that we are “His representatives on Earth” doesn’t always seem to apply. The ברית גורל is evident in great moments in history, Rav Soloveitchik’s שש דפיקות.
But the ברית-ייעוד as expressed in ברית מילה is the ברית that depends on us, and it applies even when all we experience is שם אלוקים, the blind watchmaker running the universe without purpose or design. The act of fulfilling מצוות, saying נעשה ונשמע, makes us part of something larger.