Cain facts for kids
Cain was first and thoroughly a devout and faithful man of god, until his weakened mind was manipulated by Satan (or Samael (Sammael , Sam-ael ) depending on which version of the written word is referenced, Samael can be a separate entity; the bringer of death, or another name for Lucifer).
Cain, stricken with jealousy that his loving God would choose one man over another, allowed The Snake's words to twist his sanity and in a fit of rage he slaughtered his brother Abel.
Cain Facts for Kids. Kiddle Encyclopedia.