Берешит 15:13 Комментарий: Rashi, Ramban, Radak & Sforno

וַיֹּ֣אמֶר לְאַבְרָ֗ם יָדֹ֨עַ תֵּדַ֜ע כִּי־גֵ֣ר ׀ יִהְיֶ֣ה זַרְעֲךָ֗ בְּאֶ֙רֶץ֙ לֹ֣א לָהֶ֔ם וַעֲבָד֖וּם וְעִנּ֣וּ אֹתָ֑ם אַרְבַּ֥ע מֵא֖וֹת שָׁנָֽה׃

И сказал Авраму: 'Знай о том, что твое семя будет чужим на чужой земле и будет служить им; и они поразят их четыреста лет;

Rashi

כי גר יהיה זרעך THAT THY SEED SHALL BE A STRANGER — From the birth of Isaac until Israel left Egypt was a period of 400 years. How so? Isaac was 60 years old when Jacob was born, and Jacob when he went down to Egypt himself stated, (Genesis 47:9) “The days of the years of my sojournings are a hundred and thirty years”, making together 190 years. In Egypt they were 210 years — corresponding to the numerical value of the word רדו (see Rashi in Genesis 42:2) — making altogether 400 years. If, however, you say that they were in Egypt 400 years — well, Kohath was one of those who went down to Egypt with Jacob; go and add up the years of Kohath (130), those of Amram (137), and the 80 years that Moses was old when Israel left Egypt, and you only have about 350, and you really have to deduct all the years that Kohath lived after Amram was born, and those that Amram lived after the birth of Moses (Megillah 9a).

Ramban

THAT THY SEED SHALL BE A STRANGER. This is a verse that is to be transposed, its purport being that “thy seed shall be a stranger for four hundred years in a land that is not theirs, and they shall enslave them, and they shall afflict them.” He has thus not specified the length of the period of servitude and affliction.
There are many cases in Scripture where verses must be transposed if they are to be interpreted properly. Thus: There came unto me the Hebrew servant, who thou hast brought unto us, to mock me;281Further, 39:17. The meaning being: “There came unto me to mock me the Hebrew servant.…” And all countries came into Egypt to buy corn to Joseph;282Ibid., 41:57. The meaning being: “And all countries came into Egypt to Joseph.…” For whosoever eateth leavened bread, that soul shall be cut off from Israel, from the first day until the seventh day;283Exodus 12:15. The meaning being: “For whosoever eateth leavened bread, from the first day until the seventh day, that soul.…” In that day a man shall cast away his idols of silver, and his idols of gold, which they made for themselves to worship, to the moles and to the bats;284Isaiah 2:20. The meaning being: “In that day a man shall cast away to the moles and to the bats his idols.…” Come, and hearken, and I will declare, all ye that fear G-d, what He hath done for my soul;285Psalms 66:16. The meaning being: “All ye that fear G-d, come.…” They cry unto Me, My G-d we Israel know Thee;286Hosea 8:2. The meaning being: “Unto Me crieth Israel, ‘My G-d, we know Thee.’” And they shall be Mine, saith the Eternal of hosts, in the day that I do make, even Mine own treasure, and I will spare them.287Malachi 3:17. The meaning being: “And they shall be Mine treasure, saith the Eternal.…” There are many other such verses.
The sense of the verse is: “Even though I tell you that I have given this land to your children, you should surely know that before I give it to them they shall be strangers for four hundred years in a land not belonging to them, and they shall also enslave them and afflict them.”
Rabbi Abraham ibn Ezra said [that the verse should be interpreted as follows]: “You should surely know that your children shall be strangers in servitude and affliction until the end of a four hundred year period commencing from this day of the covenant.” If so, G-d informed Abraham of the time of the redemption, but He did not inform him of the exact length of the exile. This too is correct.

Radak

ויאמר...בארץ לא להם, which will never be theirs. G’d describes the lands in which the Israelites will be exiled as countries which were not included among those of which G’d had said that Avram’s descendants would inherit them. They would remain strangers in a country or countries not theirs until the conclusion of the period of 400 years of which G’d speaks here. G’d speaks of 400 years and an additional 30 years commencing now that G’d revealed this to him. [his descendants could not begin to be exiles until Yitzchok was born, 30 years after the date of this vision. Ed.] This prophecy was fulfilled, the Jewish people leaving Egypt at the conclusion of 400 years after the birth of Yitzchok, or 430 years from the date of these revelations. On the face of it, in light of Avram having been 75 years old when he migrated from Charan, we can only account for 425 years from that time until the redemption of the Israelites from Egypt. We need to assume therefore that the vision involving the 400 years was experienced by Avram while in Charan, five years before he moved to Canaan. At any rate, G’d did not elaborate how many of these 400 years would be spent in Egypt, or even if any would be spent in Egypt. Our sages however, (Seder Olam chapter 3) have said that 210 years of the 400 are accounted for by the stay in Egypt, basing themselves on an allusion contained in the numerical value of the word רדו being 210. (compare Genesis 42,2 רדו שמה). The details of the 400 years are as follows: we start with Yizchok’s birth. He was 60 years at the time Yaakov was born, and Yaakov, by his own account was 130 years old when he answered Pharaoh’s question as to his age. We therefore have the first 190 years accounted for as predating the descent of the family to Egypt. It is totally impossible to believe that the 400 years referred to by G’d’s announcement to Avram were all spent in Egypt, seeing that Kehot, a grandson of Yaakov was among those who moved to Egypt with his family, and his age at death is given by the Torah as 133 years. We know that Moses was 80 years at the time when he made his first appearance before Pharaoh, about a year before the Exodus. If the Israelites had stayed in Egypt for 400 years, then Amram, Moses‘ father, even if he had been born during the last year of the life of Kehat would have lived for 187 years assuming that Moses was born during the last year of Amram’s life. Both of these assumptions are highly unlikely, as is the likelihood of Amram living more that 187 years without the Torah mentioning any of this. In fact, the Torah specifically states that Amram lived to the age of 137 (Exodus 6,20) It is most likely therefore, that the count of 400 years does indeed begin with the birth of Yitzchok. As long as Avram’s descendants were so few in number, they most certainly deserved to be described as “strangers” even in the land of Canaan, seeing they did not own even a small part of it. If you add the fact that Yitzchok spent many years in the land of the Philistines, and Yaakov spent 20 years with Lavan in Aram, a land which would never be part of Eretz Yisrael, neither of them could truly be perceived as a resident of the land of Canaan.