He who teaches, learns.
More French Proverbs:
If you do not have a head, you must have legs.French
A woman and a melon are hard to choose.
French
There are more foolish buyers than foolish sellers.
French
An old rat is a brave rat.
French
It is easier to abstain than to restrain.
French
In youth, one has tears without grief; in age, grief without tears.
French