What is the gist of the first half of the covenant, as contained in this Pasuk?
Rashi: That neither side (including their offspring) would ever cross the Mitzpah to harm the other, 1 and they will not see one another.
What was the Mitzpah? Why was it called by that name?
Rashi: They called the pile also Mitzpah, 1 because they said to one another, "Hashem will keep watch over us... "
Ramban: It refers to the stone that Yaakov set up as a Matzevah, which Lavan called Mitzpah because they said to one another, "Hashem will keep watch over us... " 2
Seforno: It was the name of the watch-tower nearby, which Lavan now added for an additional witness to the covenant. 3
And if this is synonymous with 'Mitzpeh Gil'ad' (refer to 31:49:2:1*, it was because they named the place after the stone.
Tosfos ha'Shalem (to 31:52 (3)), Malbim (to 31:51): Lavan wanted two witnesses, for he stipulated two matters (Shalom, and afflicting his daughters). Yaakov stipulated only about Shalom, so one witness sufficed for him.
Who is the subject of "Asher Amar"?
Ha'amek Davar: "Amar" refers to both of them. Yaakov said that it will be a Matzevah; and Lavan said that Hashem will see [if Yaakov pains his daughters].
QUESTIONS ON RASHI
Rashi writes: "Why was it called Mitzpah? Because each one said to his fellow, may Hashem watch (Yitzef)...." But it seems like only Lavan is speaking; why does Rashi need to interpret that both Lavan and Yaakov said this?
Gur Aryeh: The Torah is explaining the reason for the name Mitzpeh-Gil'ad. Lavan's words are of no significance to us; would we name a place for them? It must be that Yaakov used the same expression, and it was named for Yaakov's words (as was Gal'ed).
Rashi writes: "Each one said to his fellow, may Hashem watch... that you do not violate the covenant." But it is clear that the next Pasuk, "If you afflict my daughters" (31:50), was said by Lavan only!
Gur Aryeh: In the preceding Pasuk (31:48), Lavan was speaking, 1 that the mound is a witness and should be called Gal'ed. Our Pasuk, seemingly as an aside, tells us the reason for the associated name Mitzpah. The next Pasuk (31:50) then resumes Lavan's speech, '[... it should be witness] if you afflict my daughters....'
If only parroting Yaakov.
Rashi writes: "'For we will be hidden' - and we will not see each other." What is Rashi adding?
Gur Aryeh: They were not literally hiding themselves; rather, the distance between them would be great.