Cain is the first person born into the world. And so with the birth Cain come a number of firsts; the first birth, which therefore constituted the first family; the first sibling follows soon after with the birth of Abel. Some even believe that they were twins, although that can't be verified in the text. In Genesis 4, we have, in the story of Cain, the first recorded act of worship after the fall, the first sacrifice, the first expression of hypocrisy, the first occasion of false religion, the first act of self-righteousness, the first crime and the first opportunity for vengeance, and the introduction of common grace.