why did cain kill abel

Cain killed Abel because he was angry and resentful that God accepted Abel's sacrifice but rejected his own. According to the biblical narrative in Genesis 4, Cain and Abel both offered sacrifices to God: Abel, a shepherd, gave the firstborn of his flock, which God accepted, while Cain, a farmer, offered some of his crops, which God did not accept. This rejection made Cain very angry and downcast. Instead of repenting as God advised, Cain harbored anger and jealousy toward Abel, which led him to kill his brother when they were in the field. This act was driven by Cain's resentment and inability to master his sin, making him the first murderer in scripture. Some traditions also suggest possible deeper motives, including jealousy, lust, and sibling rivalry, but the core reason highlighted is Cain's envy and anger over God's favor toward Abel's offering.