A phrase used to warn someone to be careful of not only obvious dangers (represented by 'brave waters'), but also of those that seem harmless or quiet (represented by 'tame waters'). The underlying message is that sometimes, the most dangerous situations are those that appear safe or tranquil.
Examples
- Spanish: No te fíes solo de los enemigos evidentes, también de los amigos falsos. Cuidate tu de las aguas bravas, y de las mansas que me libre Dios.
- English: Don't trust only the evident enemies, but also the false friends. Beware of the brave waters, and may God save me from the tame ones.