If you think you know a lot and understand a lot, be certain that there is much more that you don't know.
Have a good conscience and you will always have joy. If there is any joy in the world, it surely belongs to the person with a pure heart.
I have sought tranquility everywhere, and I have only found it sitting in a secluded corner, with a book in my hands.
If we were to eliminate one vice every year, we would soon become perfect.
Don't trust your feelings, because no matter what they are now, they will soon have changed.