Genesis 4:2-6

Later she gave birth to his brother and named him Abel. When they grew up, Abel became a shepherd, while Cain cultivated the ground. When it was time for the harvest, Cain presented some of his crops as a gift to the LORD. Abel also brought a gift—the best portions of the firstborn lambs from his flock. The LORD accepted Abel and his gift, but he did not accept Cain and his gift. This made Cain very angry, and he looked dejected. “Why are you so angry?” the LORD asked Cain. “Why do you look so dejected?