What is the significance of the fact that Kayin, like his father Adam after his sin, went to live on the east side of Gan Eden?
Rashi: It teaches us that the east gathers in murderers, 1 as we derive in Parshas Va'eschanan (Devarim 4:41) . 2 Consequently, both Adam (who caused death to the world) and Kayin landed up there. 3
See Gur Aryeh, and Keli Yakar.
Refer to 4:16:1.1:1 .
That will explain the Midrash which relates how Adam met Kayin and asked him what happened with his Din Torah, to which he replied that he did Teshuvah and it was accepted.
How could Kayin settle in the Land of Nod, when Hashem had just told him that was forbidden to settle down anywhere?
Ramban: The Land of Nod was a large area, and from then on, Kayin moved from one place to another inside its borders. 1
Sha'arei Teshuvah (4:1): Through Teshuvah, his punishment "Na va'Nad Tih'yeh" was reduced.
Indeed, the Ramban explains, it was called Eretz Nod because of him.
Why was the land to which Kayin was exiled called "Eretz Nod"?
Rashi #1: Because it was the land to which all exiles moved. 1
Rashi #2: Because wherever Kayin went, the land trembled underneath him - and the prople announced 'Keep away from him - for he is the man who murdered his brother!'
Ramban: Refer to 4:16:2:1 and note.
Sanhedrin 37b: And the fact that the Torah mentions and omits the other half - "Na va'Nad" teaches us that Galus serves as half the atonement of one's sins.
QUESTIONS ON RASHI
Rashi writes: "'And Kayin left (va'Yeitzei)' - submissively; as if he could deceive G-d." How does Rashi derive this?
Mizrachi: The term 'Yatza' usually means emerging from a defined location; so here it needs further explanation.
Gur Aryeh: Kayin sought to "leave" from Hashem's jurisdiction, as if Hashem did not know his true thoughts. 1
Gur Aryeh: In other words, Kayin merely feigned submission upon hearing his verdict; he did not actually feel remorse. (CS)
Rashi writes: "'East of Eden' - That is [also] where his father (Adam) had been exiled...." Why does the eastern direction serve as a haven for exiles?
Gur Aryeh: East is called "Kedem," which also means "beginning." 1 A new beginning is open to accept - and be defined by - any new input.
Maharal (Gevuros Hashem Ch. 70, p. 322): Teshuvah requires that a person return himself to his original sinless state. Also refer to 3:24:1.2:1 .
