It's a reference to the murder of Cain, of course by Abel, in Genesis 4: 1-15, hence the title "Chapter Four," and various excerpts such as "punishment too great to bear," "from the soil his blood cries out to me," "out of the sight of the One," and being sent "far away from this land," referring to his exile in the land of Nod.
Incidentally, the band's name is arguably from this chapter, where God declared that "vengeance shall be taken on him [who kills Cain] sevenfold."