St. Francis de Sales on Fasting:
The second condition is never to fast through vanity but always through humility. If our fast is not performed with humility, it will not be pleasing to God.....
But what is it to fast through humility? It is never to fast through vanity. Now how can one fast through vanity? According to Scripture there are hundreds and hundreds of ways, but I will content myself with telling you one of them, for it is not necessary to burden your memory with many things. To fast through vanity is to fast through self-will, since this self-will is not without vanity, or at least not without a temptation to vanity. And what does it mean to fast through self-will? It is to fast as one wishes and not as others wish; to fast in the manner which pleases us, and not as we are ordered or counseled. You will find some who wish to fast more than is necessary, and others who do not wish to fast as much as is necessary. What causes that except vanity and self-will? All that proceeds from ourselves seems better to us, and is much more pleasant and easy for us than what is enjoined on us by another, even though the latter is more useful and proper for our perfection. This is natural to us and is born from the great love we have for ourselves.
