Whenever I read quotes I always wonder what is the source of the quote and who did the translation. Often this info is totally omitted.
FWIW:
It looks like the quote in this blog post is present in Saotome sensei's book
Aikido and the Harmony of Nature. I shamefully admit I don't have that book yet. I think Saotome sensei wrote that in English, so it would be awesome if he includes there a translation of this quote that he did himself, or that he personally endorses (or hopefully the translation he presents there is exactly this one).
Also
click here for the text from this blog post in a nearly identical form. Looks like the blog post is almost a direct copy and paste of the text on this page. Anyway this page indicates that this is Linda Holiday sensei's translation of a lecture given by O-sensei.