Christopher Love (1618-1651), Grace: the truth and growth and different degrees thereof: the summe and substance of XV. sermons (London: T.R. and E.M. for John Rothwell, 1652), 80.
The earliest hit I've found in Early English Books Online so far (there are many others):
1616: Leonel Sharpe, Looking-glasse for the Pope: "What is grace but glory begun? and what is glory but grace perfected?" I did not get a page number out of EEBO for this one, and when I went back the next day to procure one, I couldn't reproduce the hit (though the images were of course still there), but only (as the next earliest):
1637: Joseph Hall, Remedy of profanenesse, p. 80: "what is grace here but glory begun? and what is glory above, but grace perfected?"
I have not searched the Library of Latin Texts for anything earlier, but neither "glory begun" nor "grace perfected" comes up in the online Yale edition of the Works of Jonathan Edwards.