The Boar And The Foxes
Two foxes watched a wild boar sharpening his tusks on a tree-trunk.
“Why do you do that?” asked one of them, “the huntsmen are not out today.”
“Let that be so,” answered the boar, “but whenever my life is in danger, I shall need my tusks and there will be no time to sharpen them.”
Moral: Lost time cannot be recalled.