I desire too much

C.S. Lewis’s autobiography Surprised By Joy is easy to read. Nonetheless, he still makes quite a few references and quotes scraps of poetry without any explanation. An annotated edition would be welcome at times.

At one point he mentions a phrase in greek (non-phonetic, in greek typeset):

???????????

(I desire too much) says the footnote

So if you were properly education (unlike myself) you would know this came from right? It appears that Google does not know the origin. I was expecting logs of references to Aristotle or someone like that to show up. Zip.

The inscription appears on the hat of a painting from 1540 by Moretto da Brescia titled ‘Portrait of a Young Man ‘Portrait of Count Fortunato Martinengo Cesaresco’. I’m assuming the phrase was around long before then, but maybe not. Anybody know this?