Abel is a keeper of sheep. He represents the nomadic pastoralist, unlike Cain who is the tiller of soil, so he represents more settled urban life.

亚伯是一个牧羊人，代表着不断迁徙的牧场主，而该隐是一个农夫，他代表在城市定居的人。

耶鲁公开课 - 旧约导论课程节选

We didn't know this. It has been spoken by the uncouth swain, a rustic shepherd.

我们对此并不了解，这首诗是由一个粗鄙的年轻人，一个村夫牧羊人叙述的。

耶鲁公开课 - 弥尔顿课程节选

The poet of a pastoral elegy usually represents himself as a shepherd, a shepherd mourning the death of a fellow shepherd, and he often explains that the death of his shepherd friend is exerting a magical effect on the entire natural world.

田园挽歌诗人通常把自己写成一个牧羊人，哀悼自己的同伴的逝去，这个牧羊人常常描绘自己同伴的死,使整个自然界为之动容。

耶鲁公开课 - 弥尔顿课程节选

But there's another meaning given to shepherds as well.

但是还有另一个附加在牧羊人上的含义。

耶鲁公开课 - 弥尔顿课程节选