Sometimes, I see people complaining about how the cleric doesn't fit the literary inspirations for D&D. The way they see it, D&D is based on swords & sorcery, and there are no healing priests in swords & sorcery, so the cleric just doesn't fit.
There are a couple problems with this line of thinking. One is that D&D is not based solely on swords & sorcery; there's a big element of Arthurian legend as well, which why the paladin -- even less of a good fit -- exists. So, Howard Pyle is also a literary inspiration for D&D.
The other problem is that people are focusing too strongly on specific additions to the cleric (healing and undead turning.) It's correct to say these don't show up in swords & sorcery. However, holy characters who can deliver the occasional blessing or who are otherwise protected do show up. For example, the Roger Zelazny story "The Bells of Shoredan" has Dilvish teaming up with a priest (or monk) and entering a haunted location. The de Camp and Pratt "Harold Shea" stories (cited by name in Appendix N) has Harold's colleague acting in the role of priest when they visit the worlds of the Faerie Queen and the Castle of Otranto, specifically because a magic-using priest would fit in. The Fritz Leiber story "Lean Times in Lankhmar" features priests; the REH Conan stories and the Michael Moorcock Elric stories feature evil high priests rather than good, protagonist priests, but they are there, none the less. Tanith Lee includes priests of one sort or another in "Odds Against the Gods" and Death's Master/Delusion's Master. There's a priest who's a friend of the family in Poul Anderson's Operation Chaos; he's instrumental in casting the equivalent of a Gate or Plane Shift spell that allows the heroes to rescue their daughter from Hell.
Of these stories, Tanith Lee isn't specifically mentioned in Appendix N, but is a good fit; Zelazny and Anderson are cited for other stories, but the Dilvish stories are clearly swords & sorcery, and Operation Chaos is an obvious inspiration for a couple D&D spells (and, I would argue, for the way elementals work.) The rest are explicitly mentioned in Appendix N, and Leiber, REH, and de Camp & Pratt are said to be the most immediate influences on D&D. The cleric clearly has a literary precedent.