Johannes Aurifaber, student and secretary of Martin Luther, wrote: "Luther...wrote these words in Latin on a slip of paper and put them on his table. I, Johannes Aurifaber, wrote them down and Dr. Justus Jonas, Superintendent of Halle, who was at Halle at the same time, took the slip of paper with him." The slip of paper has long since disappeared, but the words have been preserved. As translated by James A. Kellerman (for the public domain):
No one can understand Vergil's Bucolics unless he has been a shepherd for five years. No one can understand Vergil's Georgics, unless he has been a farmer for five years.
No one can understand Cicero's Letters (or so I teach), unless he has busied himself in the affairs of some prominent state for twenty years.
Know that no one can have indulged in the Holy Writers sufficiently, unless he has governed churches for a hundred years with the prophets, such as Elijah and Elisha, John the Baptist, Christ and the apostles.
Do not assail this divine Aeneid; nay, rather prostrate revere the ground that it treads.
We are beggars; this is true.
"We are beggars" are the only words written in Luther's native German.
Martin Luther's entire goal in the Reformation was to reform the church as he knew it -- not "the Catholic church" at this time, just "the church" -- not to fragment it. Toward this end he translated the Bible for the first time from Latin into the common German language and encouraged churchgoers to understand salvation themselves. (Open source Christianity, perhaps?) He believed that salvation came through faith, not works, and that believers needed to have access to this faith on their own instead of relying on church leaders to give it to them.
And yet, these final words seem to contradict this belief. How can the man who gave the Bible to common people later say that its message is beyond their understanding? How can he say "we are beggars" after he had spent so much of his life weaning people's dependence on the church for holy truth? Even the choice of language, Latin, hides the meaning of Luther's words from the common people to whom he devoted so much effort.
But these words don't say it would take a hundred years to understand Christian salvation, or the purpose of the life of Christ. Instead, they say it takes more than a single reading of the words in one's own language to understand them fully. In modern times, too many people -- Christians and non-Christians alike -- imagine they can fully understand the lessons contained in the Bible by reading select chapters and drawing their own interpretations. No doubt this belief was especially rampant among the early Reformers who followed Luther.
Do not assail this divine Aeneid; nay, rather prostrate revere the ground that it treads. According to the translator, this is a misquoted line from the end of Statius' Thebaid which was heavily influenced by Virgil's Aeneid. Luther's use encourages his followers not to wage moral war on the Bible, or the church which uses it, but to continue to regard it as holy. He was a reformer, not a divider; he wanted to improve the church he loved, not start a new one separate from it. Regardless of what eventually happened, that was his goal.
Even those who disapproved of the church that existed, Luther was saying, must remember that the most experienced church leaders are the only ones who can hope to have a full understanding of the Holy Scriptures. Just having the book to read is not enough. Experience is sometimes more important than an an endless supply of words.