Labourers often talk of “getting a job”, or “having a job”. This conceptual metaphor of a “job” as a possession has led to its use in slogans such as “money for jobs, not bombs”. Similar conceptions are that of “land” as a possession (real estate) or intellectual rights as a possession (intellectual property).
The Online Etymology Dictionary explains that the origin of “job” is from the obsolete phrase “jobbe of work” in the sense of “piece of work”, and most dictionaries list the Middle English “gobbe” meaning “lump” (gob) as the origin of “jobbe”. Attempts to link the word to the biblical character Job seem to be folk etymology