For the idiomatic phrase, "There, but for the grace of God, go I", I take it literally to mean "There I would go, but because of God's grace, I don't."
If I'm correct, I'm confused as to where this implied negation "I don't" comes from.
Another example is given here (which incidentally explains the above phrase). I've added the implied negation in square brackets. "I too, like someone seen to have suffered misfortune, might have suffered a similar fate, but for God's mercy [I didn't]."
Is there always implied negation association with "but"? I have to say I have not seen this kind of usage very often. If there are better examples, or if this kind of implication is in fact explicitly stated somewhere, I'd be happy to hear it.