A Butterfly starts it's life out as a tiny Caterpillar who knows nothing but Hunger. And for days it Feeds on plants, getting fatter and fatter, Shedding its skin whenever it finds that it is too tightly packed in its current one (during a Caterpillar's life they Shed their skin up to Five times.). A rather disgusting creature by most people's standards.
In the middle of a Caterpillar's life they undergo something of a Metamorphosis (which is Greek for Transformation or change in shape). They Shed their skin for the last time, creating for themselves a Cocoon in which they Hibernate for nine to fourteen days. After which a beautiful Butterfly emerges from the Shell.
Usually that Butterfly lives for only a few weeks, sometimes even a couple months (those that Hibernate tend to live up to the latter).
A Butterfly is also a symbol of Faith.
For they accept their changes and beg us to do the same.