What are the implications of ?Va'yavei Kayin mi?Peri ha?Adamah??
Rashi #1: It means that he brought inferior-quality fruit. 1
Rashi #2: The Korban that he brought comprised flax-seeds (which is an inferior species.
Rashi #2: He did not take the trouble to pick something to bring as a Korban to Hashem, but brought whatever came to hand.
Hadar Zekenim: and Moshav Zekenim It means that he brought from the leftovers of his food.
See Sifsei Chachamim.
Regarding Noach, the Torah writes in Noach, 8:20 ?Vaya?al Olos ba?Mizbe?ach?. Why here does the Torah call Kayin?s Korban ?Minchah??
Oznayim la?Torah: This goes well with Rashi, who writes, in Emor Vayikra, 24:9 that whatever comes from produce (that grows from the ground) falls under the category of Minchah. 1
Oznayim la?Torah: And having called Kayin?s Korban ?Minchah? it also refers to the Korban of Hevel as ?Minchah?. See Oznayim la?Torqah.
QUESTIONS ON RASHI
Rashi writes: "'From the fruit of the earth' - of the worst quality?. How is this derived from the Pasuk?
Gur Aryeh: The Pasuk adds the term "from the produce;" meaning a distinct subset of it (in this case, in terms of its inferiority). 1
Sifsei Chachamim: Because otherwise, the Torah should have inserted the word ?me?Reishis P?ri ha?Adamah?. 2
Rashi writes: "[Kayin brought] of the worst quality." If Kayin wanted to bring a Korban of his own initiative, why did he choose his worst produce? The entire world was at his disposal!
Gur Aryeh #1: Kayin's personal trait was Ayin Ra'ah (jealousy, stinginess). Through his inferior Korban, he aimed to strengthen his personal trait, and to use it to overpower Hevel.
Gur Aryeh #2 (later in this verse): Kayin wanted to bring the opposite of Hevel's offering, as a reflection of himself - and even if that poor offering would reflect the earth's curse, so be it.
Rashi writes: "A Midrash says that it consisted of flax-seed?. What is the source for this in the Pasuk?
Mizrachi: If one spells out the letters of the word "Korban?, 1 the last letters of each name spell "Pishtan?, flax.