So said J. Gresham Machen, as quoted in Contending for Our All by John Piper.
From the beginning, the Christian gospel, as indeed the name “gospel” or “good news” implies, consisted in an account of something that had happened. And from the beginning, the meaning of the happening was set forth; and when the meaning of the happening was set forth then there was Christian doctrine. “Christ died”—that is history; “Christ died for our sins”—that is doctrine. Without these two elements joined in an absolutely indissoluble union, there is no Christianity.
And so says D. A. Carson in his sermon What Is the Gospel?