Your works, my dear Herr von Bülow, have pleased me exceedingly. I would not like to return them to your friend Ritter without enclosing an encouraging word for yourself. I append no criticism. They will get enough of that without my adding to it and I am the less inclined to enumerate weaknesses and things which have not pleased me [...] as I can see from the rest that you will soon be perfectly capable of criticising your earlier attempts yourself. [...]
Source: Letters of Richard Wagner, Vol. 1, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 130