He that reiecteth me, and receiueth not my words, hath one that iudgeth him: þe word that I haue spoken, the same shall iudge him in the last day.
John 12:48
And Iesus answered him, saying, It is written, that man shall not liue by bread alone, but by euery word of God.
Luke 4:4

Although the definition of the Gospel may have changed over time, God does not change. What is the Gospel for believers in Jesus Christ?