The leoun sit in his awayt alway
To sle the innocent, if that he may.
– Geoffrey Chaucer
The Canterbury Tales, The Friar’s Tale. The moral of the tale is that one should be virtuous, but at the same time be on alert for the temptations of the devil. For as the Friar warns in this passage, the lion always sits in his ambush to slay the innocent, if he can.