“Live all you can; it’s a mistake not to. It doesn’t so much matter what you do in particular so long as you have your life.”
Strether urges a younger man not to let caution consume the opportunity to experience life, speaking from his own painful sense of what he postponed or missed.
Source details
The Ambassadors, Book Fifth, Chapter II, Project Gutenberg #432. Strether tells little Bilham “Live all you can; it’s a mistake not to” during the Gloriani-garden conversation, speaking from regret about opportunities he believes he missed. James’s own Preface identifies this speech as central to the novel, but the line remains fictional character dialogue rather than James autobiography or universal life advice.