What did Hashem mean when He told Avraham that He would a. bless him, b. aggrandize his name?
Rashi: Hashem meant that He would: a) bless him with wealth; 1 b) add a letter to his name (and change it from Avram to Avraham).
What is the significance of the three promises that Hashem made to Avraham
Rashi #1: Traveling generally minimizes all three; Hashem therefore promised him that he would suffer no harm from the journey. 1
Gur Aryeh: Rashi then adds an additional interpretation to these phrases, because why should the blessing regarding money be dependent on Eretz Yisrael? (EK)
Shabbos 55a says that the merit of the Avos has run out! Moshav Zekenim answers that through Tefilah, it returns.
See also Ba'al ha'Turim.
Rashi continues: "We recite... 'G-d of Yitzchak... G-d of Yaakov.'" How are they alluded to in this verse?
Gur Aryeh #1: Each phrase is an additional blessing, so Chazal (Pesachim 117b) apply them to Yitzchak and Yaakov as well.
Gur Aryeh #2: "Gedulah" (greatness) is the attribute of Avraham; "blessing" comes from Yitzchak who concealed himself; "and "a great name" applies to Yaakov and the attribute of "Tif'eres." 1
For more about these three Sefiros and how they relate to the Avos, see Maharal (Netzach Yisrael Ch. 52; Chidushei Agados Vol. 4, p. 60, to Horayos 12a).
What did Hashem mean when He said to Avraham "... be a blessing"?
Rashi #2: He meant that the B'rachos were now handed over to Avraham, to bless whomever he would see fit. 3
Ramban #1: All the nations of the world would now be blessed through the merit of Avraham (and not due to their own merit).
Ramban #2: Everyone will use Avraham as an example and say to one another 'May Hashem make you like Avraham!'
Seforno: By seeking perfection and teaching the people knowledge (how to go in the ways of Hashem), Avraham would enable Hashem to rejoice with His creations.
Targum Onkelus and Targum Yonasan: Hashem meant that Avraham will be blessed.
Da'as Zekenim: Hashem told Avraham to get others to recognize Hashem and bless Him.
Hadar Zekenim: The B'rachah to Shem (Bereishis 11:27, "vi'Yehi Kena'an Eved Lamo") will not be for all of his descendants, rather, just for Avraham.
Da'as Zekenim: Hashem said, your Berachah will precede Mine (Mechayeh ha'Mesim).
Gur Aryeh: One may not conclude a blessing with two ideas (Berachos 49a). Avraham was the first of the Avos, and the others stemmed from him.
We find that Noach blessed Shem and Yefes (Bereishis 9: 26-27)! Rather, Avraham was the first who could give his merits to help the recipient (R. Uziel Milevski Ztz"l).
Seeing as Avram had already left his home country (Ur Kasdim) and was now living in Charan, why did Hashem insert the word "me'Artz'cha"?
Rashi: He meant that Avram should distance himself even more.
QUESTIONS ON RASHI
Rashi writes: "'I shall make you a great nation' - This is what we recite [in prayer], 'G-d of Avraham.'" What is the connection?
Gur Aryeh: We are only able to say this because we have become a great nation; Hashem does not unify His Name upon an individual. 1
Gur Aryeh: This means that the Avos were not merely individuals, but rather the root of the nation.
Rashi writes: "Travel results in three things: it diminishes procreation... money... one's (good) name." Mizrachi asks
Mizrachi: From this verse alone, we might have thought that Avraham would merely be unharmed. Rashi's sides with what he wrote earlier (to 12:1); the word "Lecha" teaches that he would benefit.
Gur Aryeh: "Lech Lecha" teaches that he would merit children only in Eretz Yisrael, but I might have thought that those children would be few in number due to the journey. This verse teaches that they would be a great nation and not lack in number. 1 The promise to increase his fame can be interpreted similarly.
Gur Aryeh: Thus, Rashi's words (in Rashi to 12:1), "I will make you a great nation... and make you known in the world," turn out to be based on this verse.
Rashi writes: "Distance yourself... and leave." Why does Rashi use this doubled expression?
Gur Aryeh: Avraham and Terach had already left Ur Kasdim (11:31), now Avraham was to "distance himself" even further from there. However, he had not yet left his father's household (in Charan); now he was to "leave."
Rashi writes: "'From your land' - he had already left there with his father (11:31)." Ramban asks
Gur Aryeh: We can resolve Rashi's opinion as follows. One's "Moledes" refers to one's family, not to a physical location. 1 At the time of Lech Lecha, most of Avraham's family remained in Ur Kasdim. By the time Yitzchak married (Bereishis 24), they too had relocated to Charan. 2
Rashi writes: "To make it beloved in his eyes; to grant reward for each statement." Which land was being made beloved to Avraham?
Mizrachi: The Midrash should rather be interpreted: Hashem wished to make the land Avraham was leaving more beloved in his eyes, so that he would earn more reward for leaving it nonetheless. 1 Hashem also did not reveal the destination; this was an additional reason to increase Avraham's reward.
Gur Aryeh: Rashi makes it seem that it is all one reason; Eretz Yisrael was being endeared to Avraham, and that itself would increase his reward as he eagerly awaited further instructions. This explanation can be used for all the examples that the Midrash cites.
Mizrachi: Likewise, when the Midrash cites the Pasuk, "your son, your only one, whom you love" (22:2), it means that each phrase made it more difficult for Avraham.