A proverb (from the Latin Proverbium) is some truth that is in a way important for a community and is passed on from generation to generation. By observation, experimentation, and knowledge sharing a proverb is formed. It must endure the test of time. It must be short and catchy and it must be true. (Nonetheless, proverbs are often contradictory.) By repetition it becomes immortal.
An interesting question is whether and how much the proverbs of our culture influence our thinking, consciously or unconsciously.
Proverbs of different European cultures overlap a lot.