Conditional on the existence of a Law of God (and the sort of god in whom Eliot believed) that's not so very unreasonable. It's worth distinguishing between "irrational" and "rational but based on prior assumptions I find very improbable".

(None the less, I don't think there's much rationality in the lines Will_Newsome quoted, though it does gesticulate in the general direction of an important difficulty with consequentialism: a given action has a lot of consequences and sorting out the net effect is difficult-to-impossible; so we have to make do with a bunch of heuristic approximations to consequentialism. I'll still take that over a bunch of heuristic approximations to the law of a probably-nonexistent god, any day.)