The work ethic consists of choosing productive work over unproductive activities, in order to improve the condition of oneself, one's family, and society at large.
Puritan society in New England in the 17th and 18th century exemplified the work ethic.
- The more hours Americans work, the happier they report themselves to be. Only 11 percent of Americans say they wish they could spend a lot less time on their jobs. 
Four definitions of work
The first, original definition of work was best known to Adam and Eve in their original, unfallen state.
But, in the fallen world, and from a naively secular perspective, work appears to be an ambiguous blend of joyous productivity and more-or-less unpleasant-but-necessary toil.
So, while work may be defined simply as productive activity, such a definition falls short of an enlightened, humane perspective. This naively secular view of work results, over time, in an increasingly disparate socio-politico-economic system by the error of what may be called the "Divine Right of the Work Ethic", the "rat race ethic", or the "dog-eat-dog ethic". This is the view of work in which the individual has the unqualified right to all the "proceeds of his efforts" in a secular free-for-all of economic (if not socio-economic) 'contract': "to the winner of any manner of competition---and, to the holder of any manner of advantage---rightly goes the spoil".
This secular view of work is the second definition of work, and those who, like Ayn Rand, hold to it have either no care or no comprehension of its long-term consequences. It is against those consequences that God commanded capital punishment within His own nation for those who willfully violate the Sabbath by so much as toiling and trading for personal gain on the Sabbath.
This "Divine Right" view of the work ethic is in error because it makes kings of those who merely are so driven to excel in worldly terms as to hold all individuals to account who fail to compete as capably, or at least as selfishly, as they do, and therefore are "unworthy" of consideration beyond what they have "earned". This is most notably the view of India, which has functioned as an epitome of castes since ancient times. It also is notably the view of Ayn Rand and her disciples.
The third definition of work is that which distinguishes between every important factor of the nature of production, beginning with the kind of production intended for the original, unfallen world. This third view of work holds that human individuals, as such, are inherently valuable above all other creatures, and thus who, regardless of their level of ability or inability to produce, are not to be denied, for someone else's selfish worldly glory, the joy of living in God's creation as human beings and as rightly differentiated human individuals.
This third definition of work allows slavery in terms only of economic justice. This implies that this view of work so opposes the debasement of those human individuals who find themselves owned by another (justly or not) as to command that the owner forfeit his ownership for that debasement. This third definition of work implies also a support of reparations for unjustified slavery.
The fourth "definition" of work is that which is "constructed" in opposition to all three other definitions, for the sake of saving humankind from the selfishness of "unenlightened" (real and imagined) individuals, if not also from the "superstition" (real and imagined) of the masses. This fourth view of work was most notably held by Karl Marx and the official leaders of the USSR; and, since it consists in normalizing the glory of humankind at the expense of both conforming and "non-conforming" individuals of the human kind, it immediately is bankrupt and parasitical, if not also legalistic.
This fourth view of work, however, is not equivalent to a voluntary communal work ethic, because a volunatary communal ethic may exemplify either an ambiguous or a more-or-less informed view of work.