it all started with Cain
Gen 4:8 And Cain talked with Abel his brother: and it came to pass, when they were in the field, that Cain rose up against Abel his brother, and slew him.
Gen 4:9 ¶ And the LORD said unto Cain, Where [is] Abel thy brother? And he said, I know not: [Am] I my brother's keeper?
Gen 4:10 And he said, What hast thou done? the voice of thy brother's blood crieth unto me from the ground.
Gen 4:11 And now [art] thou cursed from the earth, which hath opened her mouth to receive thy brother's blood from thy hand;
Gen 4:12 When thou tillest the ground, it shall not henceforth yield unto thee her strength; a fugitive and a vagabond shalt thou be in the earth.