This quote is originally from the novel, Mount Analogue written by Rene Daumai and Carol Cosman. I took it from the book The Experience Of Insight--A Simple & Direct Guide to Buddhist Meditation by Joseph Goldstein.
You cannot stay on the summit forever. You have to come down again, so why bother in the first place? Just this. What is above knows what is below but what is below does not know what is above. One climbs and one see; one descends and one sees no longer, but one has seen. There is an art of conducting oneself in the lower region by the memory of what one saw higher up. When one no longer sees, one can at least still know.