Genesis 4:1-16, 25:

¹ Now the man knew his wife Eve, and she conceived and bore Cain, saying, "I have acquired a male child with the help of the Lord." 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 God from the fruit of the soil; ⁴ and Abel, for his part, brought the choicest of the firstlings of his flock. God paid heed to Abel and his offering, ⁵but to Cain and his offering God paid no heed. Cain was much distressed and his face fell. ⁶ And God 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 crouches 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 God said to Cain, "Where is your brother Abel?" And he said, "I do not know. Am I my brother's keeper?" ¹⁰ Then God said, "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. ¹² If you till the soil, it shall no longer yield its strength to you. You shall become a ceaseless wanderer on earth."

¹³ Cain said to God, "My punishment is too great to bear! ¹⁴ Since You have banished me this day from the soil, and I must avoid Your presence and become a restless wanderer on earth — anyone who meets me may kill me!" ¹⁵ God said to him, "I promise, if anyone kills Cain, sevenfold vengeance shall be taken on him." And God put a mark on Cain, lest anyone who met him should kill him. ¹⁶ Cain left the presence of God and settled in the land of Nod, east of Eden...^.25 Adam knew his wife again, and she bore a son and named him Seth, meaning, "God has provided me with another offspring in place of Abel," for Cain had killed him.