What is the significance of the ladder? Why were the angels first ascending and then descending?
Rashi and Ramban #1: Yaakov was about to leave Eretz Yisrael on his way to Charan. 1 So in his dream, he saw the 'changing of the guards' - the angels of Eretz Yisrael that had accompanied up to the border of Eretz Yisrael returning to their place in Heaven, 2 and the angels of Chutz la'Aretz 3 that were waiting to accompany him until he arrived in Charan.
Targum Yonasan: The angels who had accompanied him until now were the same angels that had gone to Sedom and that, having sinned by revealing Hashem's secret (that He was about to overturn Sedom) to Lot, were denied permission to return to Heaven - until now. So he saw those angels ascend to Heaven, whereas the angels who were descending the ladder were coming to look at him. 4
Rashbam: The angels were going up and down the ladder. The order is not significant, since it is obvious that they descended first. 5
Ramban #2: Hashem showed Yaakov that (a) everything that He does in this world is via angels, and (b) that the angels do not act independently, but by the command of Hashem. 6
Ramban #3: Hashem also showed him how He was standing on top of the ladder watching over him, and He assured him that he (Yaakov) would never be under the jurisdiction of the angels, but rather directly under His personal jurisdiction (Hashgachah Peratis). 7
Ramban (citing Pirkei d'R. Eliezer), Da'as Zekenim #2: Like the Bris Bein ha'Besarim (in Lech Lecha), this was a prophetic vision concerning the four exiles, 8 at the hand of Bavel, Medes, Greece and Edom. 9
Da'as Zekenim #1, Hadar Zekenim: The ladder represents Har Sinai. The angels are Moshe and Aharon.
Tosfos ha'Shalem (6, and 20:4, citing R. Efrayim): The ladder shows that man is a microcosm of the world. His roots are in Shamayim, unlike trees. The ladder hints to three intellects (Nefashos) in man - the lowest is the source of physical lusts, the intermediate is the source of pride, anger and Ratzon, and the highest is spiritual, and aspires to Chochmah. The angels hint to Neshamos, which ascend (are drawn to the higher Sechel) or descend (towards Gashmiyus).
Ba'al ha'Turim, from the Zohar: The voice of prayer of Tzadikim is the ladder of angels. If one has intent in his prayer, the angels can ascend on it.
Tosfos ha'Shalem (11) citing Bereishis Rabah 68:12: "Artzah" hints to the Mizbe'ach; the ladder is the ramp, the smell of the Korbanos ascends to Shamayim, and the Kohanim go up and down.
Ha'amek Davar: This hinted that the Shechinah is below on the land, surrounded by angels. This is a sign that Hashgachah Peratis will surround Yaakov.
Ha'amek Davar (to 28:13): The angels represent angels of other nations. Yaakov is the foundation of Yisrael's exiles. He went to Charan, returned to Eretz Yisrael, and was exiled against to Egypt. So Yisrael went to Bavel, returned, and were exiled again.
Malbim (to 28:17): Through Tefilos and Korbanos brought here (in the Mikdash), angels ascend, and bring down an influence of abundance.
Oznayim la'Torah: The angels of G-d rose and fell with him - with Yaakov. It was because of Yaakov (the Bechir she'be'Avos) that Hashem created the world - including the angels. Therefore, when Yaakov rises, the angels rise with him, and when he falls, they fall with him.
Moshav Zekenim, Tosfos ha'Shalem (7) citing R. Yaakov of Vienna citing Ri of Orleans: But he already went to Charan, and the angels of Eretz Yisrael departed! When he returned to pray, they returned.
Hadar Zekenim (to 28:13): Angels who had given their wings to a girl (who refused their enticement, and she flew to Shamayim and became Mazal Besulah) were unable to return to Heaven until now. Alternatively, they were the angels sent to destroy Sedom.
Tosfos ha'Shalem (2, citing R. Efrayim): The two angels that accompany a person during the day ascend to record his actions that day, and two descend to guard him at night.
Because the former told them that Yaakov, whose image is engraved on the Divine Throne, and whom they were eager to see in person, was actually right there at the foot of the ladder, so they were coming to see him in person.
The Rashbam does not indicate who the angels were. See Ba'al ha'Turim, who presents a variety of explanations.
As the angels who had accompanied him until now returned to the Heaven to report to Hashem what they had done and what the situation was.
Since he was a cut above other Tzadikim, about whom the Pasuk writes, "For He commands His angels to guard you wherever you go" (Tehilim 91:11).
Pane'ach Raza: Hashem showed him that the angels ascend and descend with the Shechinah, which is with Yisrael in exile.
He showed him how the angel of Bavel climbed 70 rungs before descending, the angel of Medes, 52 rungs, the angel of Greece, 180 rungs, corresponding to the number of years that these nations would enslave his children. Then he saw the angel of Edom climbing and climbing and climbing. In response to his prayers, Hashem, citing the Pasuk, assured him that, "Even if you (Edom) will raise your nest like an eagle, from there will I bring you down!" (Ovadyah 1:4).
According to Maharal, what is the deeper meaning behind the angels' ascent and descent?
Maharal #1 (Netzach Yisrael, beg. Ch. 17, p. 92): The Midrash writes that Yaakov saw the angels overseeing Bavel, Madai and Yavan, ascending and then descending. However, he did not see the angel of Edom descend; then Hashem assured Yaakov that He would knock that angel down. Maharal explains that the first three kingdoms' downfall was due to their idolatry; and Yaakov perceived this. Edom's downfall will come about only from the upper worlds, through Mashi'ach; this is the reason for the length of the exile. 1
Maharal #2 (Chidushei Agados Vol. 4, p. 108, to Chulin 91b): Yaakov's image is inscribed on the Kisei ha'Kavod. The angels ascended to see the image above, and then descended to see Yaakov below [in comparison]. 2
Maharal (ibid. Ch. 20, p. 105): The four kingdoms are temporal; Yaakov knew that if they went up, they must come down. Anything physical has limits and an endpoint; if it arises and reaches its completion, it is essentially finished. Yaakov himself, by contrast, was above the physical. Yaakov's ascent is in terms of attachment to Hashem; only He can make Yaakov complete. The Midrash says that had Yaakov himself ascended the ladder at that time, he would never have had to descend; i.e. no other nation could ever rule over his descendants. It writes, 'If only you had believed and ascended;' for with Emunah in Hashem one attaches to Him fully.
The Gemara (loc. cit.) continues, that the angels therefore wanted to harm Yaakov. Our verses continue, "Behold, Hashem was standing over him - to protect him!" (Rashi to 28:13).
Why is "Hinei" repeated in the dream?
Ohr ha'Chayim: Normally, dreams are imaginary, and the matters are not perceived clearly. Here, everything was with utter clarity - the ladder, the angels, the Shechinah - it was a true prophecy.
Ha'amek Davar: Hinei is a Chidush, Yaakov did not know that the Shechinah is below just for him until he saw Hashem standing over him; the nations are blessed only due to Yisrael.
QUESTIONS ON RASHI
Rashi writes: "The angels who had escorted him in Eretz Yisrael... ascended to Heaven, and the angels of Chutz la'Aretz descended to escort him." But Yaakov had not yet left Eretz Yisrael?
Gur Aryeh (to 32:2, end): Taking leave of Yerushalayim can already be called starting to leave the Land, for Yerushalayim is the sanctity of the Land.
Rashi writes: "Ascending first, and afterwards descending." If the angels who had been watching him ascended first, they left Yaakov unprotected!
Gur Aryeh: That is why the next verse begins, "'Behold, Hashem was standing over him' - to protect him!" (Rashi to 28:13).
Rashi writes: "Ascending first, and afterwards descending." But why didn't the new angels descend first, so as not to leave Yaakov unprotected?