Bede

Like a bird flying away from its nest, etc. Just as a bird that neglects the eggs or chicks it was fostering and leaves them to be taken by other birds or animals, so indeed he who abandons the protection of the virtues in which he was progressing becomes a betrayer to the same virtues he seemed to possess, surrendering them to unclean spirits. Hence elsewhere it says: If the spirit of the ruler rises against you, do not leave your place. …

Commentary on Proverbs ↗