The various perspectives on the tension between Christianity and Islam open issues for the nature of religious truth and the social context of the adventures of Don Quixote. Cervantes himself was enslaved by the Moors for five years until he was ransomed. Despite this negative personal experience, his perspective on religion in Don Quixote does not cast Islam in a purely negative light, but recognises the contribution of Islam to humanity and civilization, while providing equal sly mockery of all beliefs that lack evidence. I would be interested to hear how other readers see the treatment of Islam.
Spain was at war with the Turkish Empire, and political tensions had led the Spanish king to expel all Moors, even those who were devout Christians. This tugs at the heartstrings regarding unjust persecution of 'Moriscos'. There was then, as now, a tendency to demonise Islam, but Cervantes gently invites recognition of common humanity. His device of claiming that an Islamic scholar, Cide Benengeli, wrote the book in Arabic and it was then translated into Spanish, is one main way of recognising the debt of Christian civilisation to Islam for maintaining the culture of letters through the Dark Ages. This is stated as a worry to Don Quixote, because
Don Quixote also mentions how most words starting with Al- are from Arabic.“If, however, it were the fact that such a history were in existence, it must necessarily, being the story of a knight-errant, be grandiloquent, lofty, imposing, grand and true. With this he comforted himself somewhat, though it made him uncomfortable to think that the author was a Moor, judging by the title of "Cide;" and that no truth was to be looked for from Moors, as they are all impostors, cheats, and schemers.” (2 III)
However, he comments that the Moors learnt about morality from the Christians:"What are albogues?" asked Sancho, "for I never in my life heard tell of them or saw them."
"Albogues," said Don Quixote, "are brass plates like candlesticks that struck against one another on the hollow side make a noise which, if not very pleasing or harmonious, is not disagreeable and accords very well with the rude notes of the bagpipe and tabor. The word albogue is Morisco, as are all those in our Spanish tongue that begin with al; for example, almohaza, almorzar, alhombra, alguacil, alhucema, almacen, alcancia, and others of the same sort, of which there are not many more; our language has only three that are Morisco and end in i, which are borcegui, zaquizami, and maravedi. Alheli and alfaqui are seen to be Arabic, as well by the al at the beginning as by the they end with. I mention this incidentally, the chance allusion to albogues having reminded me of it; (2.XLVII)
Here is a nice sly quote about the relation between Islam and Christianity:“Although a Moor, I know well enough from the intercourse I have had with Christians that holiness consists in charity, humility, faith, obedience, and poverty.” (2. XLIV)
Modern sensibility would regard the attitude Cervantes ascribes here to the Moors as rational. He is poking fun at the Christian claim that miracles can be believed through faith by saying Moors rely more on logic than revelation.Lothario then went on to say, "It seems to me, Anselmo, that thine is just now the temper of mind which is always that of the Moors, who can never be brought to see the error of their creed by quotations from the Holy Scriptures, or by reasons which depend upon the examination of the understanding or are founded upon the articles of faith, but must have examples that are palpable, easy, intelligible, capable of proof, not admitting of doubt, with mathematical demonstrations that cannot be denied, like, 'If equals be taken from equals, the remainders are equal:' and if they do not understand this in words, and indeed they do not, it has to be shown to them with the hands, and put before their eyes, and even with all this no one succeeds in convincing them of the truth of our holy religion.(1.XXXIII)