What is the gospel?

The Greek term “gospel” (ev-angelion) distinguished the Christian message from that of other
religions. An 'ev-angel' was news of a great historical event, such as a victory in war or the
ascension of a new king, that changed the listeners’ condition and required a response from the
listener. So the gospel is news of what God has done to reach us. It is not advice about what we
must do to reach God. What is this news?
God has entered the world in Jesus Christ to achieve a salvation that we could not achieve for
ourselves which now 1) converts and transforms individuals, forming them into a new humanity,
and eventually 2) will renew the whole world and all creation. --source, Redeemer Pres. Manhattan