Both in the world of Hither Asia [the Near East] and in the Graeco-Roman world of the Mediterranean, but especially in the latter, society had fallen, much as our society has today, into a tangle wherein the bulk of men were disappointed and angry and seeking for a solution to the whole group of social strains. There was indebtedness everywhere; the power of money and consequent usury. There was slavery everywhere. Society reposed upon it, as ours reposes upon wage slavery today. There was weariness and discontent with theological debate, which, for all its intensity, had grown out of touch with the masses. There lay upon the freemen, already tortured with debt, a heavy burden of imperial taxation; and there was the irritant of existing central government interfering with men's lives; there was the tyranny of the lawyers and their charges.
To all this Islam came as a vast relief and a solution of strain. The slave who admitted that Mohammed was the prophet of God and that the new teaching had, therefore, divine authority, ceased to be a slave. The slave who adopted Islam was henceforward free. The debtor who "accepted" was rid of his debts. Usury was forbidden. The small farmer was relieved not only of his debts but of his crushing taxation. Above all, justice could be had without buying it from lawyers. . . . All this in theory. The practice was not nearly so complete. Many a convert remained a debtor, many were still slaves. But wherever Islam conquered there was a new spirit of freedom and relaxation.
--- The Servile State