Creed

There was an old radio show..."This, I believe." Don't remember hearing it, read about it in some of Walker Percy's works.

My creed, our creed, is what we believe. Set down in writing like someone's long ago sonnet. Not a sonnet of love to wife or spouse, but a statement of love to the one that is the reason for all love.

Apostles' Creed.
Nicene Creed.
Slightly different, but mostly the same...rearrange words but the beliefs are the same and the credo is our ism.

What am I?
Exactly what me creed says I am.