Some more - this time from 'Pop's' Johnny Connors, a Wexford Traveller who learned to read an write in prison while serving time for his activities.
Jim Carroll

Cain and Abel'Pop's' Johnny Connors
I'd say the song, myself, goes back to.... depicts Cain and Abel in the Bible and where Our Lord said to Cain.... I think this is where the Travellers Curse come from too, because Our Lord says to Cain, "Cain", says Our Lord, "you have slain your brother, and for this", says Our Lord, says he, "and for this, be a wanderer and a fugitive on the earth".
"Not so Lord" says he, "this punishment is too severe, and whoever finds me", says he, "will slay me, "says he "or harass me".
"Not so", says Our Lord, says he, "whoever finds cain and punishes or slains (sic) Cain, I will punish them sevenfold".
And I think this is where the Travellers curse come from.
Anyway, the song depicts this, this er....
I call it Cain and Abel anyway; there never was a name for the song, but that what I call it, you know, the depiction of Cain and Abel.
Song; What Put the Blood