My variation: If all you have is a hammer, you'll only look for nails.

Re: OP. I always maintain the source of the quote to be Nietzsche (He was a jackdaw - aren't we all? - so I'm not claiming he's the original source. As if that means much anyway - ideas/memes are like the fashion cycle, being upcycled to 'culture' from the street.

(Its over twenty years since I read any N. so no idea which book but maybe Menschliches, all zu..)