Full Idea
The falling of drops of water will in time fill a water-jar. Even so the foolish man becomes full of evil, although he gather it little by little.
Gist of Idea
The foolish gradually fill with evil, like a slowly-filled water-jar
Source
Anon (Dham) (The DhammaPada [c.250 BCE], §9.121)
Book Reference
'The DhammaPada', ed/tr. Mascaro,Juan [Penguin 1973], p.52
A Reaction
This coincides closely with Aristotle's view of moral education. Maybe a wise man can maintain one small vice. Not all slopes are slippery.