And again she brought forth his brother Abel. And Abel was a shepherd, and Cain a husbandman.

“Cain was followed by Abel, who was killed by his brother and served as the first prophetic symbol of the City of God. He was like an alien on earth, destined to suffer cruel persecutions at the hands of the wicked men who can properly be called natives of earth because they love this world as their home and find their happiness in the worldly felicity of the earthly city.”

“And she again bare his brother Abel,.... Or "added to bare" (y), not directly or immediately, but perhaps the following year; though some have thought, because no mention is made of her conceiving again, that she brought forth Abel at the same time she did Cain, or that the birth of the one immediately followed upon that of the other: and it is the common opinion of the Jews (z) that with Abel, as with Cain, was born a twin sister, whom the Arabic writers (a) call Lebuda: the name of Abel, or rather Hebel, signifies not "mourning", as Josephus (b) observes, but "vanity", Eve not making that account of him as she did of Cain; or perhaps because by this time she became sensible of her mistake in him, or had met with something which convinced her that all earthly enjoyments were vanity; or by a spirit of prophecy foresaw what would befall this her second son, that he should be very early deprived of his life in a violent manner: and Abel was a keeper of sheep: a calling which he either chose himself, or his father put him to, and gave him; for though he and his brother were born to a large estate, being the heirs of Adam, the lord of the whole earth, yet they were not brought up in idleness, but in useful and laborious employments: but Cain was a tiller of the ground: of the same occupation his father was, and he being the first born, was brought up in the same business, and might be a reason why he was put into it. (y) "et addidit ut pareret", Pagninus, Montanus; "addidit autem parere", Cocceius, Schmidt. (z) Pirke Eliezer. c. 21. (a) Abulpharag. ut supra. (Hist. Dynast. p. 6.) (b) Antiqu. l. 1. c. 2. sect. 1.”

“And she again bare his brother Abel - Literally, She added to bear (ותסף ללדת vattoseph laledeth) his brother. From the very face of this account it appears evident that Cain and Abel were twins. In most cases where a subject of this kind is introduced in the Holy Scriptures, and the successive births of children of the same parents are noted, the acts of conceiving and bringing forth are mentioned in reference to each child; here it is not said that she conceived and brought forth Abel, but simply she added to bring forth Abel his brother; that is, as I understand it, Cain was the first-born, Abel, his twin brother, came next. Abel was a keeper of sheep - Adam was originally a gardener, Abel a shepherd, and Cain an agriculturist or farmer. These were the three primitive employments, and, I may add, the most rational, and consequently the best calculated to prevent strife and an immoderate love of the world.”