Genesis 4:4-8

But Abel brought [an offering of] the [finest] firstborn of his flock and the fat portions. And the LORD had respect (regard) for Abel and for his offering; [Heb 11:4] but for Cain and his offering He had no respect. So Cain became extremely angry (indignant), and he looked annoyed and hostile. And the LORD said to Cain, “Why are you so angry? And why do you look annoyed? If you do well [believing Me and doing what is acceptable and pleasing to Me], will you not be accepted? And if you do not do well [but ignore My instruction], sin crouches at your door; its desire is for you [to overpower you], but you must master it.” Cain talked with Abel his brother [about what God had said]. And when they were [alone, working] in the field, Cain attacked Abel his brother and killed him. [1 John 3:12]