Bereisheet (Genesis): Bereisheet > Ch 4
Cain & Abel
Adam and Eve had two children: Cain then Abel. Abel was a shepherd of flocks, and Cain was a tiller of the soil
“Cain brought of the fruit of the soil an offering to the Lord. And Abel he too brought of the firstborn of his flocks and of their fattest, and the Lord turned to Abel and to his offering. But to Cain and to his offering He did not turn”. G-d told Cain that he can improve next time, but Cain was angry and killed Abel
G-d punished Cain by making him a wanderer and an exile in the land and the soil would not continue to give its strength to him. But He placed a mark on Cain so that no one would kill him, saying “whoever kills Cain, vengeance will be wrought upon him sevenfold".
Cain dwelt in the land of the wanderers, to the east of Eden and had several generations of sons as follows: Cain -> Enoch -> Irad -> Mehujael -> Methushael -> Lemech -> Jabal & Jubal & Tubal cain
Lemech had two wives Adah and Zillah. Jabal (father of those who dwell in tents and have cattle) and Jubal (father of all who grasp a lyre and a flute) were from Adah. Tubal cain and his sister Na'amah were from Zillah. Lemech said to his wives, "Adah and Zillah, hearken to my voice; wives of Lemech, incline your ears to my words, for I have slain a man by wounding (him) and a child by bruising (him). If Cain shall be avenged sevenfold, then for Lemech it shall be seventy seven fold." (see commentary for explanation of what this means)
Adam and Eve had another son, Eve named him Seth, for G-d has given her other seed, instead of Abel, for Cain slew him. Seth had a son Enosh
Based on the Hebrew wording, Adam and Eve gave birth to Cain and Abel before they were banished from the Garden of Eden.
“fruit of the soil” means that Cain brought inferior fruit, not the best pick.
Everything that is for the sake of G-d should be of the best and most beautiful. When one builds a house of prayer, it should be more beautiful than his own dwelling. When one feeds the hungry, he should feed him of the best and sweetest of his table. When one clothes the naked, he should clothe him with the finest of his clothes. Whenever one designates something for a holy purpose, he should sanctify the finest of his possessions; as it is written (Leviticus 3:16), "All the fat is to G-d."
Adah was called so because she was despicable to Lemech and removed from him. עָדָה is the Aramaic translation of סוּרָה, turn away.
[The story was] that Lemech was blind, and Tubal-cain was leading him. He spotted Cain, who appeared to him as an animal, and he told his father to draw the bow, and he killed him. As soon as he learned that it was his grandfather Cain, he clapped his hands together [in anguish] and clapped his son between them and killed him. So his wives separated from him, and he attempted to appease them by saying “hearken to my voice” (saying that he did not kill intentionally)
Tubal cain was born in the seventh generation from Cain
Tubal cain made swords and instruments of war. Thus he may have continued the evil deed of his ancestor Cain
Research & Analysis
Cain hasn't seen anyone die before, and thus did not realize the consequence of his attack on Abel. This is why G-d doesn't punish Cain with death.
Some people want to kill Jews because G-d has chosen them for a special destiny. The right thing to do is to help Jews fulfill their destiny, allowing all humanity to be closer to G-d.