Do not draw your sword to kill a fly.
More Korean Proverbs:
In the valley where there are no tigers the hare is king.Korean
Even children of the same mother look different.
Korean
The nicest woman is your own; the nicest harvest is your neighbors.
Korean
The bad plowman quarrels with his ox.
Korean
A turtle can only get on it by sticking its neck out.
Korean
The thief hates the moon.
Korean