Beware of a silent dog and still water. meaning

HOME PROVERBS

hurt

Beware of a silent dog and still water.

it is believed:
That things that seemed calm, like a silent dog and still water, could still hurt you. Stagnant water can be poisonous with bacteria and a silent dog can still bite you. Thw same with people, that might be silent while they are thinking of how to hurt you.