And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.
Matthew 24:14

In this age, the emphasis is often on a nonoffensive, nonconfrontational gospel, but such a gospel is disobedient to the command of Christ in Matthew 28:19-20,

Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all things that I have commanded you; and lo, I am with you always, even to the end of the age.

There is only one gospel.  It is eternal and changeless.  It is the gospel of the Kingdom–the only gospel Jesus or His disciples or Paul preached, and the same gospel we must preach today.  Unfortunately, seldom is the gospel preached in the way Paul preached it in Romans 1, Acts 17:2-3, etc.  Chapter 1 of Romans, for example, reveals what must shock a Jew; that Christianity is not some new invention, but the fulfillment of the same message the Hebrew prophets had proclaimed.

~from Dave Hunt in Apples of Gold, May 2

For I am not ashamed of the gospel of Christ, for it is the power of God to salvation for everyone who believes, for the Jew first and also for the Greek.  For in it the righteousness of God is revealed from faith to faith; as it is written, “The just shall live by faith.”
Romans 1:16-17