Mastema is prominent in only one surviving text, the Book of Jubilees, a Jewish work usually dated to the second century BCE, where he leads spirits who test and afflict humanity, proposes Abraham's trial, and works against Moses in Egypt, always with God's permission rather than in open rebellion. What makes Mastema interesting to historians of religion is less the character himself than the company he keeps: Second Temple Jewish literature of this period names several distinct adversarial figures, Mastema, Belial, and Satan among them, without settling whether these are the same being under different names, overlapping roles occupied by different beings, or titles rather than proper individuals at all.
Some scholars read Mastema as essentially a functional title, meaning something like "the one who opposes" or "hostility" personified, used by the author of Jubilees in a role that other contemporary texts assign to Belial. This multiplicity is itself the historical evidence: rather than a single settled figure of ultimate evil inherited whole from earlier tradition, the very idea of one consolidated adversary, the later Christian and rabbinic Satan or Devil, appears to have crystallized gradually out of exactly this scatter of overlapping Second Temple figures, of which Mastema is one of the more clearly attested examples.