Here's something of C.S. Lewis found at Open Culture just before I dipped into Matthew Arnold's The Function of Criticism at the Present Time—
Every age has its own outlook. It is specially good at seeing certain truths and specially liable to make certain mistakes. We all, therefore, need the books that will correct the characteristic mistakes of our own period. And that means the old books. […] If we read only modern books […] where they are true they will give us truths which we half knew already. Where they are false they will aggravate the error with which we are already dangerously ill. The only palliative is to keep the clean sea breeze of the centuries blowing through our minds, and this can be done only by reading old books.
Both Arnold and Lewis feel pretty timeless right now.