French Proverb

This week, we learned a proverb from some of our friends.  This proverb is:

1) the motto of Louis XII,
2) the devise of a French city called Nancy from a 1477 battle, and
3) the motto of the region of France called Lorraine which has changed hands between Germany and France in battle 3 times:

Qui s'y frotte, s'y pique.

Which, being interpreted, means when one risks attacking someone, one will regret it.