Cain and Abel
The first human beings to be born were Cain and Abel, the two children of Adam and Eve.
Cain, the first-born, was plowed the fields, and Abel became a shepherd.
Cain was always busy, he labored to get food from the earth, which refused to grow on its own accord as it used to in the days before Adam and Eve’s sin. Abel, however, spent much of his time thinking about his parents’ mistake, and of ways of making amends for it.
In a spirit of repentance and gratitude Abel brought some of his best young lambs as an offering to G‑d. Cain saw this, and he, too, wanted to offer something to G‑d. He, therefore, selected the most exquisite first fruits of the year as his offering. But Cain’s offering was not accepted by G‑d because he did not give it wholeheartedly and of his own free will, as Abel did. When Cain observed that G‑d did not care for his offering, he became angry at his brother and decided to kill him.
G‑d, the All-seeing, the All-merciful, rebuked him gently. He asked him why he was angry, and why his tolerance was fallen. If his offering was not accepted, should he not take it as a sure sign that he had not done well? He ought to take heed, or repentance would come too late.
The Murder of Abel
Cain discussed this with his brother. While they were in the midst of talking over what is right and what is wrong, Cain rose against his brother and killed him. When G‑d asked him where Abel was, he answered, “I do not know. Am I my brother’s keeper?”
G‑d said to Cain, “What have you done? Your brother's blood cries out to Me from the earth. And now, you are cursed even more than the ground, which opened its mouth to take your brother's blood from your hand. When you till the soil, it will not continue to give its strength to you; you shall be a wanderer and an exile in the land.”
Cain was sorry for doing his evil deed and he prayed to G‑d to make his punishment lighter: "Behold You have driven me today off the face of the earth, and I shall be hidden from before You, and I will be a wanderer and an exile in the land, and it will be that whoever finds me will kill me." Cain's desperate plea was heard. G‑d assured Cain that nobody would kill him until the seventh generation. And a sign appeared on Cain’s forehead to serve as a warning that nobody should kill him.
Cain wandered all over the earth, till he finally settled in Nod, “the land of wandering,” east of Eden. He had many, many children. They multiplied and were powerful One of the last descendants of Cain was Yabal, the first man to live in a tent and to raise cattle. Another descendant was Yubal, who was the first to play the lyre and the flute. Another was Tubal-Cain, who was the first man to make tools out of metal. Tubal-Cain had a sister Naamah.
Tubal-Cain’s father, the sixth generation from Cain, was Lemech. Lemech grew old and became blind. One day Tubal-Cain, his youngest son, led him out into the fields to hunt for food. Far off, Tubal-Cain saw something moving that looked like a monstrous animal. He advised the blind Lemech to aim his arrow towards it, and Lemech shot. When they got closer, they discovered to their great sorrow that they had killed Cain.