I grabbed that one from a Facebook group I belong to- Quote of the Day-
https://www.facebook.com/groups/184090004964607/Many of the quotes I post come from memory with Google helping me get them correct and attributed properly. Sometimes the quote has some relevance to some item in the news, life, or a passing thought. When I am at a loss , I go to Brainy Quote-
http://www.brainyquote.com/ and grab one that suits my mood.
I have posted before that any member that wishes may post a Quote of the Day if one hasn't yet been posted. I usually post for the next day after 11 PM. The only caveat would be that a quote here shouldn't be overly controversial , religious, or political.