The Secret of the Evangel or The Mystery of the Gospel

What does the Greek word mustērion mean? Our English Bibles typically render this word as "mystery," or "secret." What does the Greek word euaggelion mean? Our English Bibles typically render it as "gospel," "evangel," or "good news." How does our understanding of these words impact the preaching of the cross? Is prophecy about the cross the same as the preaching of the cross, or are they different things? Christianity has allowed biases and misunderstanding to overwhelm it; with the result being many Christians cannot tell anyone with clarity what the "gospel" is! So, what exactly does the Apostle Paul mean when he says: "the secret of the evangel?" As a believer it is crucial to understand these words, and the significance they hold for all of humanity!