William O’Flaherty runs the Essential C.S. Lewis website and has a first Saturday monthly feature on words misattributed to the great Jack Lewis. Yesterday he highlighted a quote that is actually from Lewis, but in isolation it reads contrary to its intended meaning in the story.
Seize the day, as it were. Take that hill. Do the thing.
O’Flaherty explains where these words are found in The Magician’s Nephew and what they mean. He has a long list of questionable quotations. See his list of the top five from 2015 here, including two that were spoken by Anthony Hopkins while playing Lewis, which doesn’t make them Lewis quotations.