“Don't think about why you question, simply don't stop questioning. Don't worry about what you can't answer, and don't try to explain what you can't know. Curiosity is its own reason. Aren't you in awe when you contemplate the mysteries of eternity, of life, of the marvelous structure behind reality? And this is the miracle of the human mind—to use its constructions, concepts, and formulas as tools to explain what man sees, feels and touches. Try to comprehend a little more each day. Have holy curiosity.”

Variant transcription from "Death of a Genius" in Life Magazine: "Then do not stop to think about the reasons for what you are doing, about why you are questioning. The important thing is not to stop questioning. Curiosity has its own reasons for existence. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery each day. Never lose a holy curiosity."
Source: Attributed in posthumous publications, Einstein and the Poet (1983), p. 138