Do not beat the grass to startle the snake

There is a set of thirty-six strategies/proverbs of ancient China that have been presently compiled and interpreted by several authors in a context of either the art of war or the art of business. One of them is : Beat The Grass To Startle The Snake
which original meaning is that punishment for someone can serve as a warning to others although today people use the idiom in different contexts :

Before military action, be sure to ascertain the enemy’s situation, or
Sometimes it is best not to directly attack the snake –uh, your opponent, or
In your business make a trial-and-error approach to launch new products, among many others

But we like it best as a negative sentence rather than a positive one :

Do not put threats to the opponent since his/her answer may be unexpected