In popular thought the “capital sin” of sloth revolves around the proverb “An idle mind is the devil’s workshop.” According to this concept, sloth is the opposite of diligence and industry; it is almost regarded as a synonym for laziness and idleness. Consequently, acedia has become, to all practical purposes, a concept of the middle-class work ethic. The fact that it is numbered among the seven “capital sins” seems, as it were, to confer the sanction and approval of religion on the absence of leisure in the capitalistic industrial order.
But this is not just to render superficial and shallow the original concept of acedia as it exists in moral theology; it is to transform it completely.
The opposite of acedia is not industry and diligence but magnanimity and that joy which is a fruit of the supernatural love of God. Not only can acedia and ordinary diligence exist very well together; it is even true that the senselessly exaggerated workaholism of our age is directly traceable to acedia, which is the basic characteristic of the spiritual countenance of precisely this age in which we live. (118)
Josef Pieper | Faith, Hope, Love