Then she bore again, this time his brother Abel. Now Abel was a keeper of sheep, but Cain was a tiller of the ground.
Genesis 4:2
Surrounding context
4:1 Now Adam knew Eve his wife, and she conceived and bore Cain, and said, "I have acquired a man from the LORD."
4:2 Then she bore again, this time his brother Abel. Now Abel was a keeper of sheep, but Cain was a tiller of the ground.
4:3 And in the process of time it came to pass that Cain brought an offering of the fruit of the ground to the LORD.