Why did Cain fail even though he had the same opportunity as Abel?
Cain failed because he had no faith. Though he had the same opportunity as Abel, he did not see any significance in what God said. His problem was spiritual—he lacked faith, which led to his failure, just as Esau later saw no significance in spiritual things.
Les explains that Cain had the same opportunity as Abel, but his problem was no faith. Cain did not see any significance in what God said. This same spiritual blindness appeared in Esau, who sold his birthright for a morsel of food, was not bothered by it, and later wept when he missed the blessing. Les points out that Esau saw no significance in spiritual things, just as Cain did. The failure was not due to unequal opportunity but to a heart that did not value or believe God's word.