(1) Now the Human knew his wife Eve, and she conceived and bore Cain, saying, “I have gained a person with the help of יהוה.” (2) She then bore his brother Abel. Abel became a keeper of sheep, and Cain became a tiller of the soil. (3) In the course of time, Cain brought an offering to יהוה from the fruit of the soil; (4) and Abel, for his part, brought the choicest of the firstlings of his flock. יהוה paid heed to Abel and his offering, (5) but to Cain and his offering [God] paid no heed. Cain was much distressed and his face fell. (6) And יהוה said to Cain,
“Why are you distressed,
And why is your face fallen?
(7) Surely, if you do right,
There is uplift.
But if you do not do right
Sin couches at the door;
Its urge is toward you,
Yet you can be its master.” (8) Cain said to his brother Abel … and when they were in the field, Cain set upon his brother Abel and killed him. (9)יהוה said to Cain, “Where is your brother Abel?” And he said, “I do not know. Am I my brother’s keeper?” (10) “What have you done? Hark, your brother’s blood cries out to Me from the ground! (11) Therefore, you shall be more cursed than the ground, which opened its mouth to receive your brother’s blood from your hand.

מפרי האדמה OF THE FRUIT OF THE GROUND —of the worst fruits (Genesis Rabbah 22:5); there is an Agada which says that it was linseed (Midrash Tanchuma, Bereshit 9).

SHALL IT NOT. Many commentators explain se’et (be lifted up) to mean thy sins will be forgiven. However, it appears to me that se’et means thy face will be lifted up. For it is previously written, and his countenance fell (v. 5). And his countenance fell indicates shame, as in how then should I hold up my face (esah panai) (II Sam. 2:22). The meaning of our verse is: if you will do good, then you will lift up your face. Surely then shalt thou lift up thy face (tissa fanekha) without spot (Job 11:15) is similar.

ואליך תשוקתו AND UNTO THEE IS ITS LONGING — The longing of sin; it refers to the evil inclination. This is continually longing and desiring to make you sin.

Re᾽uven, thou art my firstborn, my might and the beginning of my strength, the excellency of dignity, and the excellency of power:

“Cain said to Abel his brother. It was when they were in the field. Cain rose up against Abel his brother and killed him” (Genesis 4:8).
“Cain said to Abel his brother. It was when they were…” – about what were they quarreling? They said: ‘Let us divide the world between us.’ One took the land and one took the movable property. This one said: ‘The land on which you are standing is mine.’ That one said: ‘What you are wearing is mine.’ That one said: ‘Take it off.’ This one said: ‘Fly.’ As a result: “Cain rose up against Abel his brother and killed him.”
Rabbi Yehoshua of Sikhnin said in the name of Rabbi Levi: Both of them took the land and both of them took the movable property. Regarding what, then, were they quarreling? Rather, this one said: ‘The Temple shall be built in my domain,’ and that one said: ‘The Temple shall be built in my domain,’ as it is stated: “It was when they were in the field,” and “field” is nothing other than the Temple, as it says: “Zion will be plowed like a field” (Micah 3:12). As a result: “Cain rose up against Abel his brother…”
Yehuda bar Rabbi said: They were quarreling over [who would wed] the first Eve. Rabbi Aivu said: The first Eve had returned to dust. Regarding what, then, were they quarreling? Rabbi Huna said: An extra twin sister was born with Abel. This one [Cain] said: ‘I will take her, as I am the firstborn.’ That one [Abel] said: ‘I will take her, as she was born with me.’ As a result: “Cain rose up.”

ויאמר קין אל הבל AND CAIN SPAKE TO ABEL — He began an argument, striving and contending with him, to seek a pretext to kill him. There are Midrashic explanations of these words, but this is the plain sense of the text.