Three sons of the murderer Lamech, himself a descendant of the killer Cain, are credited with founding various useful arts (Gen 4:20-22). What are we to make of this?

The irony is strange indeed. Cain’s descendant Lamech both begets children who give the world useful arts and himself commits the world’s second recorded murder. Jabal was (after Abel) the original nomadic herdsman; Jubal, the original musician; and Tubalcain, the original blacksmith. It is hardly as if such arts are frowned upon in themselves in the Bible; David was a shepherd and a musician, and as a general, a user of the blacksmith’s arts. So it is certainly striking that these origin stories are sandwiched between two murders. This is probably not accidental. Probably, in keeping with the theme of not seeking forbidden knowledge (Gen 3) or building towers to heaven (Gen 11), we are to infer that such practices, however fine they might be, pose a danger in the form of pride.