Finally found the David Bentley Hart quote about early Christian socioeconomic practices I’ve been looking for:

“How quickly, after all—a few centuries at most—even the most prominent features of the faith were altered almost beyond recognition by the imperial culture into which the faith was integrated from the time of Constantine on. How easily what, by any sound historical judgment, appear to have been essential elements of the Christianity of the first generations became at best accidental to the Christianity of the next few centuries, and then as often as not entirely absent from the Christianity that ensued in the next few centuries after that, as social, political, and ideological conditions shifted around the communities of believers. In the earliest generations of the church, for instance, the radical insistence on a communism of goods and the fierce condemnation of personal wealth were anything but marginal, prudential, or dispensable aspects of the Christian life. They were the very essence of what it meant to belong to “the Way,” as the earliest Christians called their faith. “So, therefore, no one of you who does not bid farewell to all his own possessions can be my disciple” (Luke 14:33). The form of life that was Christianity, by definition, entailed a total renunciation of private property and power; or, rather, it did not merely entail that renunciation: such renunciation was precisely what defined a believer as belonging to the new creation established in Christ. To die with Christ in baptism and to be raised anew was to die to a life lived according to property and privilege—“Bios”, as it were—so as to enter into that eternal life—“Zoe”—proper to the communal nature of Christ’s body. So too the rejection of military service, the proscription of participation in capital punishment, and the refusal to use the courts to seek legal redress for grievances or to have crimes punished. So too the disdain for those who lord it over others (Matt. 20:25; Mark 10:42; Luke 22:25), who dwell in palaces and wear fine clothes (Matt. 11:8; Luke 7:25), or who live in dainty luxury (James 5:5). None of these was merely an option, a private spiritual hygiene, an elective moral discipline. All of this simply was Christianity. And one need only compare all of it to the later social and institutional realities and theological concerns of imperial Christendom, or to modern Western culture’s comfortable bourgeois cult of civic respectability and personal prosperity, or to the free-market capitalist orthodoxies and ridiculous gun-obsessions and barbarous nation-worship of the “Christianity” indigenous to contemporary America (even among many Catholics and Orthodox)—or, for that matter, to countless other variants of Christian adherence throughout history and across the globe—to find oneself hard-pressed to see how any of this could truly be regarded as a single continuous faith, rather than merely a series of historical ruptures, divagations, accidental sequelae, and frequent total inversions. In fact, the entire way of life that was at one time the very essence of Christian existence, with its contempt for wealth and its civic dereliction and its hostility to the mechanisms of power by which societies and nations and empires thrive and survive and perpetuate themselves, is the very way of life to which most Christian culture throughout the centuries has proved implacably hostile. (Those damned hippies. Those irresponsible delinquents. Those unpatriotic bastards. Those sentimental snowflakes. Those seditious socialists.) It would be no exaggeration to say that, viewed entirely in historical perspective, cultural and institutional “Christianity” has, for most of its history, consisted in the systematic negation of the Christianity of Christ, the apostles, and the earliest church.”

David Bentley Hart, Tradition and Apocalypse, 33-35.