Tetzaveh: Chapter 4
"And it came to pass at the end of days"

Rabbi Shimon tells us that "the end of days" means impurity, while "the end of right" is holiness. He says that Cain's offering was not accepted because it "came to pass" "at the end of days," so it came from the Other Side. Abel included a small portion for the Other Side in his offering with the largest portion for God, while Cain included the largest portion for the Other Side. We are also told that Job did not properly arrange his offering either.