Galatians 1:6-9 (ESV)
I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel—  not that there is another one, but there are some who trouble you and want to distort the gospel of Christ.  But even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed.  As we have said before, so now I say again: If anyone is preaching to you a gospel contrary to the one you received, let him be accursed.
There is only one Gospel. Yet Paul can take the Galatian Christians to task, in verse 6, for deserting Christ and turning to another gospel. He explains what he means in verse 7: we believe in another Gospel when we distort what the one true Gospel is. This is very sobering. Many more aberrant belief systems distort the Gospel while claiming to be the Gospel they distort. Recently, the blogosphere and even the mainstream media has been busy discussing whether Jesus is necessary for salvation or not. When the Bible talks about the triumph of grace, God defeating all His enemies, evil being killed … does it mean that all people eventually go to heaven? Not if the Gospel message of the Scriptures is true.
Paul is not shy to say what should happen to those who distort the Gospel (vs. 8-9). The response to what Paul says here in verse 7 – 9 is to take great care to know the biblical Gospel and to believe and preach nothing else but the biblical Gospel. Those who maintain that different beliefs should just get along and agree cannot maintain their argument in the light of Galatians 1. The different belief systems do not agree. We can love those who believe a different Gospel, but we cannot say that their Gospel is true. We must either hold tenaciously and lovingly to the one true Gospel because of what Paul says here, or we must abandon what Paul says here and deny its truthfulness. The latter is simply not an option. We must recognize that there is only one Gospel. We must know it. We must preach it. And we must never surrender it no matter what the pressures on us are.
There is no better Gospel than the one we have received. We cannot make it better. We cannot come up with something else. We can rejoice in it and seek to tell it and demonstrate it to all whom God puts in our pathway.