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. For am I now seeking the approval of man, or of God? Or am I trying to please man? If I were still trying to please man, I would not be a servant of Christ. (Galatians 1:9-10 ESV)
The gospel is a message of hope from God that is tied with a promise of everlasting life for those who believe that Jesus died for their sins. Preaching anything different from that would come with a curse as Paul puts it. The reason is because false teachers would be misleading people, something that God does not take lightly. Some people may follow religion but lack genuine faith while others may live with guilt, not knowing that their sins have been forgiven.
“Every word of God proves true; he is a shield to those who take refuge in him. Do not add to his words, lest he rebuke you and you be found a liar” (Proverbs 30:5-6).
The gospel of Christ is not a religion. It is not up for revision and it was never meant to be divided into denominations. It is the Good News of God backed by his power and authority. We are to be good stewards by studying his Scripture and understanding in its true context. Then, in my opinion, we are to explain it in terms so people can better understand him and the hope that we have in Jesus.