"Now we command you, beloved, in the name of our Lord Jesus Christ, to keep away from believers who are living in idleness" (2 Thessalonians 3:6). St. Paul is not here recommending a life of work, work, work, ignoring the sacred. A young lawyer working a 70-hour a week should not draw comfort from Paul's words, unless indeed the lawyer's work is infused with the Holy Spirit.

Instead, Paul is warning against a particular type of unworldly excess, a laying down of tools in expectation of the Second Coming. He appears to have heard that some of the Thessalonians were withdrawing from the world to prepare for the end days, which they thought in 53 C.E. were coming any day now. The early Christians were, of course, not the last to form such expectations. Readers of a certain age will remember the Johnstown cult. Such millenarianism breaks out repeatedly, as it did recently in the 35 million copies sold of the first of the Rapture books.

"I must work the works of Him who sent Me while it is day; the night is coming when no one can work. As long as I am in the world, I am the light of the world" (John 9:4-5). By a mechanism that the sociologist of religion Rodney Stark has described in historical detail, cult-formation is natural in any religion that emphasizes a distinction between the sacred and the profane, the Lord's work and the world's work. The Church of Faith, as Stark calls it, grows restive under the rule of the Church of Power. The holy ones repeatedly break off from the world and form cults in expectation of Christ's coming. And if they believe the time is late and the end is near, they stop working, as St. Paul complained. One of these cults we call Protestantism, and some of the Radical Reformation - such as the Anabaptists in the sixteenth century - were willing on account of imminent salvation to go to the stake singing hymns.

Earlier, in the eleventh century in southern France, the Albigensians, or Cathars - derived from the Greek term meaning "pure" - would in their last days withdraw from Satan's world to enter God's kingdom as "Perfects," as they called themselves. The believing Cathars who were short of perfection would go about their worldly business until their end days. As St. Paul said, "work with quietness and eat your own [earned] bread." But when the Cathars were called to perfection - and many were called from the elite of Languedoc society during the twelfth and thirteenth centuries - they gave away all their goods and followed Jesus.

Stark notes that in European history, or for that matter in Islamic or Jewish history, such purifying moves did not usually come as an upwelling from the poor and oppressed. On the contrary, the cults tended to be led and staffed by the rich - or, to be more precise, the formerly rich, such as St. Francis of Assisi. The riches of Mammon (the word in Aramaic simply means "wealth") were spurned in the name of purity. No need to work. Just pray.

The Church of Power did not look kindly on the Cathars. The ironically named Pope Innocent III arranged in 1209 a crusade of northern knights, led by Simon de Montfort, in which fully 200,000 withdrawers from the world were sent out of it prematurely. The Inquisition of later notoriety was invented by the papacy in 1284 to deal with the persistent remnant of Cathars. So the Church of Power has always been suspicion of what it regards as excessive withdrawal from God's beloved world of work. Augustine, who was not exactly easy going about worldly pleasures, nonetheless was harsh, with fire and sword, against the holier-than-thou Donatists.

The social science of worldly goods called economics could be expected to have a similar attitude, right? Not working is bad. Stay in the world. Pump up the economy. But economics doesn't. On the contrary, economists view withdrawal from the world, a refusal to work - after all, what is the point of work if Christ is coming soon? - as what they call "leisure." "Leisure" in economic analysis is anything but paid work. The economist views volunteer "work" visiting the sick or feeding the poor or just sitting there praying in expectation of the End Times as something you do, literally, in your spare time. Work or pray. No worries: your call, or calling. Whatever.

What is St. Paul complaining about, then? He goes on to remind the Thessalonians that when he was visiting them he himself worked "night and day." In a verse that sounds to an economist like a lesson in the budget constraint he declares, "Anyone unwilling to work should not eat." The economist would put it a little differently: "Anyone unwilling to work," she would say, "will not in fact eat, unless he has support from outside the marketplace. But no blame attaches," says the non-Christian economist. "It's his choice. Whatever."

Notice that the economist is not angry at the idle person. That's the force of the Valley-girl "whatever" that one feels comes after most refusals by economists to think seriously about ethics. The idler "chooses leisure" or, in case he does not have that support from a mother or a charitable person, he "chooses" starvation. St. Catherine of Siena (1347-1380) starved herself to death at age 33, the age that Jesus died, by refusing to eat anything but the communion host. The French mystic Simone Weil followed St. Catherine, starving herself to death during the Second World War, age 34. An economist is likely to analyse such behaviour as a mere choice, like choosing between chocolate and vanilla ice cream, and leave it at that. Whatever.

St. Paul, along with some theologians such as Thomas Aquinas up to the present, would have taken a less neutral view of Catherine and Simone. Such radical withdrawing from the world strikes some Christians as spiritual pride. I am proud that I am so humble, and Satan swoops down at the last minute to claim my soul. An old New Yorker cartoon shows two monks walking in the cloister, one saying to the other, "But I am holier than thou." (And the Devil swoops in at the last minute and takes his soul, exhibiting the sin of pride that he is not proud.)

What, then, is the theological gripe against these "holier than thou"? Why isn't withdrawal from the world orthodox (remember, in Greek the word means "upright opinion")? What's not upright about withdrawing from the world? The answer I would give is that the world's work in Christianity is dignified.

If Christianity is to be, in Nietzsche's sneering characterization, a slave religion (we Christians embrace the characterization with satisfaction) it cannot downgrade what slaves do - that is, work. Paul, in requiring that people work if they are to eat, was standing against the ethos of a slave and patriarchal society in which dignified people, such as non-slaves and non-women and free male citizens of Rome like Paul, specifically did not work "night and day," or at all.

St. Benedict's Rule in about the 530rd year of the Christian Era at Monte Cassino uses the same word for work in the fields and the "work of God." The monastic formula was laborare est orare - to work is to pray. Work in the world is a form of prayer, if done with God in mind: "Idleness is the enemy of the soul," said Benedict. This work-praising tendency in Christianity made it easy for urban monks in the high Middle Ages such as Aquinas to justify the urban work of say, merchants, as creative work, like God's.

The obligation to self-development is the obligation to use God's gifts. The Christian version is reformulated in 1673 by Joseph Pufendorf of Leipzig, Heidelberg and Lund thus:

"It seems superfluous to invent an obligation of self-love. Yet ... man is not born for himself alone; the end for which he has been endowed by his Creator with such excellent gifts is that he may celebrate His glory and be a fit member of human society. He is therefore bound so to conduct himself as not to permit the Creator's gifts to perish for lack of use ..."

Thus Comus tempting the Lady in 1634 argues that from niggardliness in using God's gifts:

"Th'All-giver would be unthanked, would be unpraised Not half his riches known ... And we should ... live like Nature's bastards, not her sons."

The liberal Christian tradition of the urban friars, such as Francis and Dominic and Aquinas, recommended working on God's gifts. "Albert the Great and [his student, St.] Thomas," writes Lester Little, "brought about the emancipation of Christian merchants." They were not commending unlimited greed, but a purposeful buying low and selling high. "The honest merchant, for all these writers, was a man deserving of the profit he made, for they considered it as payment for his labour (quasi stipendium laboris)." Profit paid for alertness. This is the virtue of the liberal man, in the words of Aquinas: "by reason of his not being a lover of money, it follows that a man readily makes use of it, whether for himself, or for the good of others, or for God's glory."

One wonders where the work-praising came from, since in the Greek and Roman world work was so very undignified, and the collection of feudal rents by the genteel was precisely why they did not work at anything but war and courtesy. After Adam's curse, of course, a human was to earn his bread by the sweat of his brow. Yet Judaism praised work - "Seest thou a man diligent in his work? He shall stand before kings." Maimonides wrote in the early thirteenth century: "One who make his mind up to study Torah and not to work but to live on charity profanes the name of God, brings the Torah into contempt, extinguishes the light of religion, brings evil upon himself, and deprives himself of the life hereafter." This sounds rather like Paul scolding the Thessalonians.

The Christians, of course, go further than the Jews praising diligence or the Muslim's listening to an inspired merchant of Mecca. God himself, in the form of God's only begotten son, became in the words of the Creed "truly human." God was a carpenter, the Christians say, and not merely metaphorically as among Jews and Muslims, a maker of the world, but literally in the sweat of his brow. That is the startling Christian story.

But wherever it came from historically, God appears to want it. He wants us to live and choose in his created world, though not since the Fall in the Edenic part. To put it economically, God wants us to face scarcity. He wants it not because he is a trickster who is amused by seeing us struggle with disease and the law of gravity in our pain-filled and finite lives. He so loves us that, after Eden, he wants us to have the dignity of choice. That is what free will means.

Denys Munby said to me once, "In Heaven there is no scarcity and in Hell there is no choice." In the created world there are both. The dignity of free will would be meaningless if a choice of one good, such as apples, did not have what the economists call an "opportunity cost" in, say, oranges. If we could have all the apples and oranges we wanted, "living in idleness," as Paul put it, with no "budget constraint," no "scarcity," we would live as overfed pet cats, not as human beings. If we have free will, and therefore necessarily face scarcity, we live truly in the image of God.

Scarcity is necessary for human virtues. Humility, said Aquinas, answers among the Christian virtues to the pagan virtue of great-souledness, or magnanimity, which Aristotle the pagan teacher of aristocrats admired so much. To be humble is to temper one's passions in pursuing, as Aquinas put it, boni ardui - goods difficult of achievement. To be great-souled - which, in turn, is part of the cardinal virtue of courage - is to keep working towards such goods nonetheless. No one would need to be courageous or prudent or great-souled or humble if goods were faciles rather than ardui.

The virtue of temperance, again, is not about mortification of the flesh - not, at any rate, for Christian thinkers like Aquinas (there were others, descendants of the Desert Fathers, who had another idea). On the contrary, this side of Christianity says, we should admire the moderate yet relishing use of a world charged with the grandeur of God. It is the message of the Aquinian side of Christian thought that we should not withdraw from the world. On the contrary, as Jesus was, we should be truly, and laboriously, and gloriously human.

Deirdre McCloskey is Distinguished Professor of Economics, History, English and Communication at the University of Illinois at Chicago. She is in Australia as the 2013 Eminent Speaker of the Economic Society of Australia, and is this evening delivering the 2013 John Bonython Lecture hosted by the Centre for Independent Studies. She is the author of sixteen books, including The Bourgeois Virtues: Ethics for an Age of Commerce and Bourgeois Dignity: Why Economics Can't Explain the Modern World.