The Two Most Important Days In

This saying has no connection to Twain. Quote Investigator found no evidence of it before 1970, when a minister named Ernest T. Campbell used a version in a sermon at Riverside Church in New York, prefaced with "it has been said." The earliest attribution to Twain appeared online around 2011 as the quote went viral on social media — roughly a century after Twain died in 1910. Researchers at the Center for Mark Twain Studies note that the quote's sentimental, purpose-driven tone is inconsistent with Twain's characteristically skeptical voice.