1520 December: Erasmus, In epistolam Iacobi canonicam paraphrasis at James 2: "Therefore, the man who has by his flattery shown a preference for the undeserving rich man [(diuitem immerentem)] over the deserving poor man [(pauperi promere[n]ti)] is accountable for all the sins which are usually perpetrated against the love of neighbor, since he has broken this part of the law of love" (Collected works of Erasmus, ed. Robert D. Sider, vol. 44, Paraphrases on the epistles to Timothy, Titus, and Philemon; the epistles of Peter and Jude; the epistle of James; the epistles of John; the epistle to the Hebrews, trans. John J. Bateman (Toronto: University of Toronto Press, 1993), 149; Tomus secundus continens Paraphrasim D. Erasmi Roterodami in omneis apostolicas epistolas (Basil, 1532), p. 336; cf. Opera omnia Desiderii Erasmi Roterodami VI.10 (Leiden: Brill, 2014), p. ). With thanks to Dr. Owen Ewald for his help with the abbreviation "promereti".
1549, "Coverdale", translation of Erasmus' Paraphrasis of James 2:1-7: "He yt hath..preferred the vndeseruing rich man before the deseruing pore man" (Oxford English dictionary).
1891, Henry Sidgwick: "the distinctive principle of the English system is that Government is not to discriminate between the deserving and the undeserving poor, but to secure to all who are destitute a minimum of subsistence under conditions deterrent but not painful: and this principle would be rejected as too harsh by many who now accept it, were it not for the assumption that private almsgivers will be ready to undertake the task of discrimination which Government declines, and to accord more generous and tender treatment to those who have fallen into distress through undeserved calamities" (Henry Sidgwick, The elements of politics (London: Macmillan & Co., 1891), 202). A debate over the justice of the distinction seems to have raged during the Victorian period, so there is much more where this comes from. Indeed, according to the OED, the roots of it might be traced back, in English at least, to
c. 2001, supposedly "Dorothy Day" (pseudo-Dorothy Day): "The gospel takes away our right forever, to discriminate between the deserving and the undeserving poor." Though Dorothy Day (1897-1980) does indeed seem to have been of this opinion, and invokes the distinction more than once, I have yet to track this very sentence to any of her known works or sayings, not even in the Catholic Worker-sponsored Dorothy Day Library on the Web. Nor was I able (in mid-July of 2015) to get Google to turn it up in a search limited to the years before 2001. What is more, Day specialists and authors James Allaire (Webmaster, Dorothy Day Library on the Web), Robert Ellsberg (Publisher, Orbis Books), Jim Forest (like some of the others a Day biographer), and Phillip M. Runkel (Archivist, Dorothy Day-Catholic Worker Collection, Special Collections and University Libraries, Raynor Memorial Libraries, Marquette University) all concur in suspecting it (which is to say the very sentence) of inauthenticity (correspondence with Steve Perisho, week of 13 July 2015). My guess is that it derives from (at best) some second party's encapsulating summary or reformulation of her position (itself somewhat unoriginal (Sidgwick and others, above)).