It is not conflict of opinions that has made history so violent but conflict of belief in opinions, that is to say conflict of convictions.

The way to transmute your iron duty into gold in everyone's eyes is this: always deliver more than you promise.

A sedentary life is the real sin against the Holy Spirit. Only those thoughts that come by walking have any value.

In order to acquire intellect one must need it. One loses it when it is no longer necessary.

The magnitude of a progress is gauged by the greatness of the sacrifice that it requires.

What we do is never understood, but always merely praised or blamed.

The sick are the greatest danger for the healthy; it is not from the strongest that harm comes to the strong, but from the weakest.