Near the end of Book I, chapter 17 of Our Mutual Friend, Charles Dickens writes:
There are the beggars on horseback too, in another sense from the sense of the proverb. These are mounted and ready to start on the highway to affluence.
When I read this, I thought that the "proverb" Dickens was alluding to was "If wishes were horses, beggars would ride." But a note in the Everyman edition of the book says that the relevant adage is "Set a beggar on horse-back, and he'll ride to the devil."
I have two questions: 1. Which of these two expressions is older? 2. Did they arise independently, or is one in some sense a retort to the other?
A quick survey of Ngram Reader results reveals an instance of "if wishes were horses" from 1719, in the translator's preface to Monsieur Bossu's treatise of the epick poem:
...language from his royal majesty ensued, and then we were formally introduced to the fraternity by their assumed titles. "If wishes were horses," says the proverb, "beggars would ride;" and, as if in exemplification of the adage, these ... [snippet]
From W. Goodall, The Adventures of Captain Greenland (1752), we have this:
But there is an ancient saying, that, set a Beggar on Horseback, and he will ride to the Devil. Now, whether that Saying was verify'd here or not, we shall not presume to understand.
But we also seem to have a truncated version of the saying in John Trapp, Solomonis Panaretos: Or a Commentarie Upon the Books of Proverbs, Ecclesiastes, and the Song of Songs (1650):
The Crown of the wise is their riches; but yet give them a foole, you put a sword into a mad man's hand; the folly of such fools will soon be foolishnesse. Why? was it not foolishnesse before they were rich? yes, but now it is become egregious foolishnesse. [Greek quotation omitted] the earth cannot beare the insolencies of such. Set a beggar on horseback, &c.
All three of these quotations suggest that the adages are already thoroughly established at the time of the writers' citing them.