The gospel is good news, not good advice. The gospel is not primarily a way of life. It is not something we do, but something that has been done for us and something that we must respond to. In the Greek translation of the Old Testament — the Septuagint — the word euangelizo (proclaim good news) occurs twenty-three times. As we see in Psalm 40: 9 (ESV) — ‘I have told the glad news of [your] deliverance in the great congregation’ — the term is generally used to declare the news of something that has happened to rescue and deliver people from peril. In the New Testament, the word group euangelion (good news), euangelizo (proclaim good news), and euangelistes (one who proclaims good news) occurs at least 133 times.
D. A. Carson draws this conclusion from a thorough study of gospel words: Because the gospel is news, good news… it is to be announced; that is what one does with news. The essential heraldic element in preaching is bound up with the fact that the core message is not a code of ethics to be debated, still less a list of aphorisms to be admired and pondered, and certainly not a systematic theology to be outlined and schematized. Though it properly grounds ethics, aphorisms, and systematics, it is none of these three: it is news, good news, and therefore must be publicly announced.
– Tim Keller