A fast day is the eve of a feast day.
More Spanish Proverbs:
If you want to know what a man is really like, notice how he acts when he loses money.Spanish
The ass knows well in whose face be brays.
Spanish
Let him that has a mouth not say to another, Blow.
Spanish
If you eat it up at supper, you cannot have it for breakfast.
Spanish
However bright the sun may shine, leave not your cloak at home.
Spanish
He who has sheep has fleeces.
Spanish