Proverbs undergo a kind of evolution - people are making remarks and observations continually, and every now and again something that someone says or writes is picked up and repeated. Due to its wisdom and/or aptnes of phrase, over time it gains the status of a proverb.
Some of the ones we use probably go back thousands of years and have transferred from one culture to another. A proverb can gain in strength by having some poetical quality of alliteration or rhyme but this rarely translates well into another language.
