Genesis 4:2-4

And [later] she gave birth to his brother Abel. Now Abel kept the flocks [of sheep and goats], but Cain cultivated the ground. And in the course of time Cain brought to the LORD an offering of the fruit of the ground. 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]