No other Gospel
The meaning of the word gospel derives from the greek word (euaggelion) which is translated as Good News or Good Message in english.
Many have used this term dogmatically to support their unbiblical agendas, without a careful explanation of what the term imply one ends up in heresy unaware. This term is widely used throughout the New Testament to describe the Good News that comes by Jesus Christ. Often times it is referred to as the Gospel of God (Romans 1:1, 1Pe_4:17) or the Gospel of Christ Jesus (Romans 1:6, Rom_1:9) meaning that it came not from man but from God.
There are but two gospels in this world, one is the true Gospel of God or of Christ and the other is the false gospel of man, either you have the true gospel or the false one. The false gospel is that one that is man made and is preached by unregenerate man. People have invented many gospels of which we classify them all under the false gospel, they are not many gospels but divisions inside the false gospel. There is the prosperity gospel that many seem to cling to and their end is damnation, the psychological gospel, the so called demonic gospel and many others, they all present another Jesus who differs from the biblical Jesus, and all of them claims to be preaching the gospel, this is due to the fact that none of them has ever given themselves time to study from the bible what the gospel is. They spend much time preaching than studying the word of God.
You probably are marveling by now what is the gospel, well the bible gave us the true meaning of what these good news is in Paul's first letter to be Corinthians 15:3-8
1Co 15:3 For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures,
1Co 15:4 that he was buried, that he was raised on the third day in accordance with the Scriptures,
1Co 15:5 and that he appeared to Cephas, then to the twelve.
1Co 15:6 Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep.
1Co 15:7 Then he appeared to James, then to all the apostles.
1Co 15:8 Last of all, as to one untimely born, he appeared also to me.
This is the biblical meaning of the word Gospel, the Good news is about Jesus' death and resurrection. Anyone who comes preaching and does not present this gospel is not sent by God but he is a deceiver and a false prophet. The bible is very strict on this matter and does not allow us to compromise the Gospel. Let us look at some few examples of how the bible teaches us on how to respond to these false gospels.
1. Gal 1:8 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.
Gal 1:9 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.
2. 2Jn 1:9 Everyone who goes on ahead and does not abide in the teaching of Christ, does not have God. Whoever abides in the teaching has both the Father and the Son.
2Jn 1:10 If anyone comes to you and does not bring this teaching, do not receive him into your house or give him any greeting,
2Jn 1:11 for whoever greets him takes part in his wicked works.
3. 2Co 11:4 For if someone comes and proclaims another Jesus than the one we proclaimed, or if you receive a different spirit from the one you received, or if you accept a different gospel from the one you accepted, you put up with it readily enough.
4. Rom 16:17 I appeal to you, brothers, to watch out for those who cause divisions and create obstacles contrary to the doctrine that you have been taught; avoid them.
5. Eph_4:14 so that we may no longer be children, tossed to and fro by the waves and carried about by every wind of doctrine, by human cunning, by craftiness in deceitful schemes.
The bible is a book from God and about God, everything inside it is God centered. Do not let them deceive you by any means; there is only one Gospel of God and that is the gospel of Christ.