Section — Slater, Manual of Moral Theology
2. Covetousness
Covetousness or avarice is the inordinate love of wealth, It is not sinful to value and seek after money in moderation, but the love of money becomes inordinate when it causes a man to be too close and niggardly in spending it, too eager and absorbed in acquiring it, and ready to do what is wrong in order to come at it.
It is of itself a venial sin, but it becomes mortal when it leads to the transgression of a precept which binds under grievous sin. Although it is of itself only a venial sin, yet it is very dangerous because of man’s proneness to it, and because the vice is apt to grow fast by what it feeds upon, until it becomes mortally sinful. Holy Scripture frequently condemns it and warns us against it.1
1 1 Tim. vi 9, etc.
p. i, 99
Covetousness is opposed to liberality by defect, while prodigality is opposed to liberality by excess. Liberality is the virtue which moderates the love of wealth and inclines us to spend it well, according to the dictates of right reason. Prodigality inclines a man to squander his wealth on unworthy objects, or to give more than he should do, so that he is not able to live according to his state of life, or he is unable to fulfil his obligations, or he reduces his family to beggary.
p. i, 99–100