Aesop's Fables (1884)
217. The Wild Boar and the Fox.
A Wild Boar was whetting his tusks against a tree, when a Fox coming by, asked why he did so; "for," said he, "I see no reason for it; there is neither hunter nor hound in sight, nor any other danger that I can see, at hand." "True," replied the Boar; "but when that danger does arise, I shall have something else to do than to sharpen my weapons."
It is too late to whet the sword when the trumpet sounds to draw it.
Aesop's Fables: A New Revised Version From Original Sources (translator not identified), 1884 . Illustrations by Ernest Henry Griset (1844-1907), John Tenniel (1820-1914) and Harrison Weir (1824-1906). Available online at Project Gutenberg.