“Can you imagine silver leaves waving above a pool of liquid gold containing singing fish? Twin suns that circle and fall in a rainbow heaven, another world in another sky? If you’d like to come with me, I’ll show you all this – and it will be, I promise you, the dullest part of all. Come with me and you will see wonders that no Human has ever dreamt possible. Or stay behind and regret your staying until the day you die.”
- The Doctor -
As the first Buddha said, “Just as people test the purity of gold by burning it in fire, by cutting it, by examining it on a touchstone, so exactly should you, my disciples, accept my words after subjecting them to a critical test and not out of reverence to me.” (http://www.buddhanet.net/pdf_file/buddha-teachingsurw6.pdf)

Where did you get that quote from the Doctor from? Was it an episode or a book? It’s beautiful . . .
Thanks for reading! I saw first saw this quote in the early to mid 1980’s, in the Making Of Doctor Who book (apparently so… I spent a while trying to trace the source a few years later). It’s been attributed to David Whitaker (supposedly as part of an old Doctor Who script) but it apparently wasn’t in any aired script and may have been a one-off for an earlier publication. References to this quote go back even further than the book I saw it in: another reader referenced a BBC magazine called The Listener that mentions this quote in 1975 (attributed to a Whitaker script but again, apparently not something that ended up being broadcast). That may well be the earliest reference.