This was found in his desk a few days after he died:

“No one can understand Virgil’s Georgics unless he has been a farmer
for five years. No one can understand Cicero’s letters unless he has
busied himself in the affairs of a great empire for twenty-five years.
No one can presume to have indulged in Holy Scriptures sufficiently
unless he were in charge of all the churches for one hundred years
with the prophets Elijah and Elisha, John the Baptist, Christ, and the
Apostles. Do not seize hold of this divine aeneid, but adore its
tracks with humility. We are beggars, this is true.”

He wrote it in Latin, except for “we are beggars.” This he wrote in
German, to give it emphasis.