Religious principles are also a blemish in any polite composition, when they rise up to superstition, and intrude themselves into every sentiment, however remote from any connection with religion. It is no excuse for the poet, that the customs of his country had burthened life with so many religious ceremonies and observances, that no part of it was exempt from that yoke. It must for ever be ridiculous in Petrarch to compare his mistress, Laura, to Jesus Christ. Nor is it less ridiculous in that agreeable libertine, Boccace, very seriously to give thanks to God Almighty and the ladies, for their assistance in defending him against his enemies.
[David Hume, "Of the Standard of Taste", par. 36.]
This is an interesting passage, because the association of the erotic/romantic and the religious is very close to being universal; and perhaps more immediately to the point, a Petrarch who wouldn't associate Laura with religious tones would not have written the poetry he did, and likewise with Boccaccio and his stories, and that would not have been an obvious improvement in the field of 'polite composition'. Nor, if you actually look at either Petrarch or Boccaccio, do the religious elements seem particularly intrusive. It's worth quoting an example of what Hume is complaining about, from Boccaccio's Decameron (in "Conclusion of the Author"):
Most noble damsels, for whose solace I have addressed myself to so long a labour, I have now, methinketh, with the aid of the Divine favour, (vouchsafed me, as I deem, for your pious prayers and not for my proper merits,) throughly accomplished that which I engaged, at the beginning of this present work, to do; wherefore, returning thanks first to God and after to you, it behoveth to give rest to my pen and to my tired hand.How ridiculous this very mild expression of an author who is responding to criticisms of his work as being immoral or impious may be, is perhaps more controvertible than Hume suggests; at the very least, the association of God Almighty and the ladies is not itself ridiculous. One is inclined to suggest that Hume's Scottish Presbyterian background is showing through here. It seems a touch of bigotry to deny a poet the right to appeal to God Almighty and the ladies; particularly as it is a right that poets have had in possession from time immemorial, and God Almighty and the ladies are the only consistent patrons of poetry through the ages.