Mind Blown! Not finding the source of the quote but lots of bloggers have internalized it. E.g.

You simply can't imagine anything unless it exists already, because when you imagine something you are actually tuning into a particular frequency, and if that frequency didn't exist in the Universe you wouldn't be able to tune into it. So when you imagine yourself with something you want you are tuning into a real thing that already exists ... https://www.lawattractionplus.com/2011/07/secret-law-of-attraction_20.html