Never Lose Your Beginner's Spirit

Another good translation is "Never Forget Your Original Intention". The phrase is composed of the words Beginner's Mind (shoshin), 忘る (read wasuru) meaning "to lose (something)" and ベカらズ (read bekarazu) meaning "must not; should not"

This is an ancient Japanese saying going back to at least the 13th century. In a slightly different form it appears as part of a Samurai Code which appears in English(ie "shoshin wo wasurubekarazaru koto") but does not appear at all in the Japanese sources that we could find .