It is ful fair a man to bere hym evene,
For al day meeteth men at unset stevene.
Modern English:
It’s well to be upon one’s guard, I mean,
Since all day long we meet the unforeseen.
– Geoffrey Chaucer
The Canterbury Tales, The Knight’s Tale. Taught to him by years of experience, the Knight says it is wise to be always on guard for the unexpected. He makes this observation when Arcite is unaware of Palamon’s presence in the woods.