Sahih Bukhari Volume 004, Book 055, Hadith Number 548.

Narated By Abu Huraira : Allah 's Apostle said, "Treat women nicely, for a women is created from a rib, and the most curved portion of the rib is its upper portion, so, if you should try to straighten it, it will break, but if you leave it as it is, it will remain crooked. So treat women nicely."