Genesis4:20

She, and everyone else before the world-wide flood, probably had many more children than those mentioned. Sometimes the text says that someone “bore other sons and daughters,” and sometimes it does not say that, but we can assume that it was true. When people lived 900 years, the portion of their life in which a woman was capable of bearing children would be many times longer than the 35 years or so that is true for women today. We can safely assume that the population of the earth increased rapidly because couples just kept having children.

The root word behind the name Jabal means “stream, or flow;” it can also mean “to bring forth, to carry along.” It is also the root word for the names of his brothers, Jabal and Tubal. Thus, context must indicate what they were the flow of. In this case, the father Lamech, was able to do more than name a child and hope that he would become the flow of something (the initiator of, or the controller of something), he was able to make it happen.

This is indeed the word for “father,” but it could indicate other things, such as “head, chief, or leader.” In this case it makes more sense to think that he became the leader, or was given leadership over, those who lived the nomadic, herd-raising lifestyle, for there were already people living as nomads before he was born. I believe he was given this leadership role by his father, Lamech, and he became more knowledgeable about the breeding and care of animals than anyone before him. He took it to a whole new level.

This word is usually translated “cattle or livestock,” but it also could mean “possession or purchase.” Thus there seems to be an emphasis on the marketing aspects of raising these animals. For them, marketable animals were usually sheep, goats, cows and bulls.